It's unreal how bad the initial rollout was between HTTP/streaming and stdio, bearer auth and OAuth. Virtually every client/MCP server pair had a different portion of that matrix implemented.
The prose on the page is very unclear. My best interpretation is that they want to continue supporting stdio but that they don’t want it to be its own special protocol. The obvious way to do that would be to speak ordinary HTTP (version 1.1? 2?) over stdio and to use the MCP-over-HTTP protocol over the resulting HTTP transport.
This would be more complex to implement for a simple server, but it’s not exactly difficult.
I’m not really a fan. But if you’re building a protocol that needs to map to HTTP anyway, then maybe using the HTTP binding everywhere is not totally awful.
In the flip side: I’m currently designing an AI-adjacent protocol, and it will be able to map to WebTransport, but I don’t plan to define non-WebTransport HTTP bindings unless a very compelling reason appears. The main implementations will not use HTTP at all :)
> if you’re building a protocol that needs to map to HTTP anyway
I don't think there is any guarantee that HTTP will always be involved. For example I might be calling a local LLM via CLI/script on a server with a stdio MCP connector that just runs other CLI commands, and never sends any HTTP traffic.
Right. But there is a lot of real-world usage of MCP-over-HTTP-over-the-Internet, and a lot of “harnesses” want to support that use case, so they’re stuck either implementing the HTTP-based protocol or using a shim.
Those are mostly at a different layer. You can speak Thrift or Avro or Protobuf over stdio or HTTP or TCP or carrier pigeon.
gRPC spans layers, and it uses HTTP in a more intrusive way than even MCP does — it expects to own the entire URL space at the IP/port in question. Using gRPC in a nontrivial way for MCP would be fairly heavy-weight: you would probably need to set up reflection and figure out how to bind all the MCP calls to it unless you just use it as a tunnel.
I am very curious how many MCP servers will actually implement all of this:
"MCP authorization today is built around a person approving access in a browser. That works well for interactive clients, but more and more of the callers are agents running as cloud workloads with their own identity, acting on behalf of a user who isn’t present, or delegating narrower authority to sub-agents. We want MCP servers to have a standardized way to recognize and trust those agent identities, built on existing standards rather than pasted API keys and long-lived tokens.
The work here covers finalizing Demonstrating Proof of Possession (DPoP) and driving its adoption, and defining an opinionated path for agent identity and delegation through Workload Identity Federation, the ID-JAG grant behind Enterprise-Managed Authorization, and standard token exchange. We will also continue to grow our engagement with the OAuth standards bodies, including the IETF OAuth and WIMSE working groups, to help the underlying standards evolve with the building blocks that agent identity needs."
I think the spec overcomplicates everything honestly. Its not that hard to add a long running auth token and put it in the MCP config as a header to send along and then avoid all the extra special rules.
"Oh no it's a long lived token that's bad"
Put it in a secret manager like 1pw cli and now start an agent...
How does the agent auth with 1pw? How do you give it access to only the credentials it needs, with an approval flow and revocation? Who renews the token? You’ll likely end up reinventing something pretty close to what MCP is building towards.
Authn/authz is one of those things that can be really simple for pointed use cases but gets really complex when you need to support everything.
The perceived difficulty is not what is at play here. People and employers are not comfortable with the idea of long lived credentials to begin with -- and even less in the 'hands' of an AI agent.
The complexity in these protocols is mostly essential in nature (to the extent that you're not willing to totally reinvent the protocol, like AAuth).
That doesn't work well for enterprise-managed MCP, where you actually do want the user to overtly authorize their agent to user their identity for MCP services, rather than the MCP server just setting a user ID in an HTTP header somewhere and everyone hoping for the best.
What people who care about security want -- finely grained permissions that guarantee security boundaries, at the expense of bad UX
What most end users want -- for the machine to do what they want, as often as possible, while bothering them as little as possible
Windows' UAC journey is a microcosm of the space. The real long-term win is defining ground level permissions around common use cases, so that when composed they can alert as rarely as possible.
But that's an all-of-ecosystem change: the OS (providing usable boundaries), applications (updating to use minimal boundaries), and users (understanding what they'll need to approve/deny).
Why, directionally all of them. What they say is obviously true. Having to manually click things in the browser is a bottleneck and will be less and less acceptable for serious users.
And the individual work attached to making that transition will be done by agents.
agree. it seems there are two streams and they could diverge or converge?
1. workloads use existing credentials
support RFC 7523 and OIDC discovery, 'trust the trust (credentials) which has already been established'. basically extend current dominant NHI paradigm.
2. DPoP
mandate a signed proof for each request. so tie credential to a client-held key and specific request detail or context. viable to do at scale with #1, or does it diverge (e.g. because most #1 methods as most are not designed for DPoP?
It is viable. Think of workload identity federation as the mechanism for the client to get an bearer token initially, and DPoP as the mechanism for the client to present the access token to a resource server. Each DPoP proof is entirely self-contained, so resource servers don't need to manage any additional state. The only new state is the (usually ephemeral) private key held by the client:
1. Client generates a private/public keypair and uses it to generate DPoP Proofs -
JWTs containing the entire public key embedded as a JWK within
2. Client presents credentials (WIF, client creds, auth code, etc.) to the Authorization Server along with a DPoP Proof
3. Authorization Server validates DPoP Proof and adds a claim to the access token containing the thumbprint - the SHA-256 hash - of the public JWK.
4. Resource Servers will now see the thumbprint claim and now know the access token needs to be presented with a fresh DPoP proof.
5. Clients generate fresh DPoP proofs and send them along with the access token
There are lots of additional details around nonces, timestamps, per-request binding, etc. but DPoP can be rolled out to any HTTP system that speaks Bearer token already.
I've been working on a protocol that promises all of that and more. We're currently targeting a NOSTR/Buzz demo in the coming week as a proof of concept.
Even now, the mcp server itself doesn't have to implement all of the possible security options. You can use something like agentgateway to act as an auth proxy for your mcp servers.
WIF works far better when you don’t want humans in the loop. For example, we’d do our development on cloud instances, those have identity linked to our humans via our IdP. Our IdP governs all access, for example: it lets devs use Datadog. If an agentic workflow needs Datadog access and the MCP requests OAuth that slows the loop down. At the same time, we don’t want Service Accounts everywhere because we need to be able to answer “who” a lot for compliance reasons.
it's not easier for agents to work with. it's easier for organizations to work with.
for agents, they're essentially the same thing - remote endpoints, and instructions on how to call those endpoints. what MCP brings is centralized updating and distribution of the instructions, and a promise that the skill and the REST api won't be out of sync with each other.
the one thing that skill.md+REST doesn't solve is how you get that skill.md to somebody else's computer, and how you ship an update to somebody else's computer once they've got a copy of the skill. if that's a problem you need to solve, you can either start inventing skill.md distribution protocols, or you can just use MCP.
I am developing my first custom agents. I am finding that if I offload some workflow to another agent (e.g. Claude Code), the simplest way to control what it can or cannot do is via an MCP server (which only lets it access tools that I develop/approve myself). I do need that control in the corporate environment.
Maybe there are easier ways to do it, just learning and exploring now.
Maybe I just need more patience, but I took a look at some tools that have MCPs, and their "setup guide" on how to start using the MCP server really gave me brain damage. Is this really easier to work with?
It seems like organizations will mostly want remote access via http and the other flavors of MCP aren’t so useful? Although, I suppose if you install an app locally, it might have an MCP interface.
It is the automatic distribution and automatic update. The questions isn't "how does one download a text file to another persons computer?". It is "how does someone with a skill.md file on their computer discover that a new version of that file is available".
This isn't a "bottleneck" but rather a capability (or lack thereof). As you add more and more capabilities, especially ones relevant to enterprise situations like authentication, authorization, governance, etc. then MCP starts to pay off.
If you do not need those capabilities, then you do not need MCP. And then you shouldn't use it. But if you do need those capabilities then it might be worth using MCP rather than inventing your own way to do them.
I see. In my head it would be something like the agents harness having a list of services it interacts with, reaches out to service.com/agents.md for a fresh copy every so often and uses that to resolve the relevant tool calls.
But for enterprise there may be teams, each developing their own way to do it. Then there will be many different ways that it is done throughout the enterprise, which is hard re: governance. Better/easier to adhere to an industry standard which can be audited, especially for enterprises where that is a legal requirement.
That isn't a reason you should use it, just an explanation about why someone has to use it.
>reaches out to service.com/agents.md for a fresh copy every so often and uses that to resolve the relevant tool calls.
that is basically what MCP is. except it answers all the questions that your version handwaves away - how often do you get a fresh copy, how do you describe the relevant tool calls, how are the tools organized, and how does auth work.
Not all agents have access to a sandbox/cli/code execution environment to run arbitrary api calls etc. MCP helps by essentially having another tool call without needing a sandbox. If you do have a sandbox, then might as well do codemode if you insist on mcp https://blog.cloudflare.com/code-mode/
Instead of the CEO mandating that the API server has to be agent compatible (where who knows what that means), they can just say "our product has an MCP".
On a technical level, who knows what it actually is (is it actually the new stateless version, does it have all the endpoints, is the regular API more feature-rich, do I need those features for my workflow?, etc.). But at a surface-level, the intention is clearer, and lets other gears (like sales and marketing) keep spinning without getting bogged down in technical details.
All that, yes. And at a technical level, it is much easier to have a single spec to follow. When a customer complains that their client isn't working, I can point at how they aren't following OAuth discovery properly or something.
To the LLM, the a skill input is deterministic, inflexible, and outputs natural language.
A REST API (not the REST itself, but modern output being JSON primitives) outputs are deterministic, flexible, but doesn't output natural language.
An MCP as an input is deterministic, flexible, outputs natural language.
Then we ask the same question on whether the LLM gets back a response that is deterministic. Skills output are not deterministic, it requires LLM to generate tokens to take action. It may or may not take the specific actions instructed by the skill.
So, Skills + REST API = MCP only if you can deterministically call on the REST API.
At my company Parallel AI, I just built an extremely well documented openapi spec and then MCP builds from that. Complete alignment with UI/API/MCP so there is no extra work.
Are others doing this?
It seemed obvious to me, but I don't hear others saying it.
Oh sorry I didn't explain that we are not dumping the entire endpoint list to the MCP. We have 400+ endpoints so this would be terrible.
We tag each endpoint by category in the OpenAPI spec and require the MCP to request actions by tag and optional query term. At most we return 10 endpoints at a time and the LLM can request more using pagination.
These tags also create your categories in API doc websites like swagger/mintlify so its a win win.
I created MCP AQL, which is an extension to the MCP spec, specifically to reduce the bloat for MCP tools.
It only has five CRUDE endpoint: Create, Read, Update, Delete, and Execute using a GraphQL-like structure for tool calling of the operations within the endpoints. It's very efficient, and robust. there's all kinds of exemplar tools and components to make adapters for any MCP server. You don't even need to rewrite your own MCP server. Just create an adapter for it.
Just because a MCP server offers 100 MCP tools doesn't mean that they all have to be in your context. Any decent harness will let you filter out ones you don't want. And to take that concept further you really should be designing specialized subagents that only have access to a small subset of total MCP tools in the first place.
I work on an MCP server and I agree. There is no need to make MCP servers the gateway for agentic or programmatic integration - that's exactly what API servers handle out of the box. The value of MCP servers is fine-toothed access on a tool-by-tool basis and leaving output digestion to the LLM.
LLMs do GREAT utilizing well-defined tools to accomplish tasks. Look at Datadog's MCP, instead of figuring out a multitude of filter and navigation options your LLM can immediately navigate to what you want and extract the precise data you need. Tool instructions with defined I/O structures let LLMs fly.
But for a nightly cron job pulling down stats or something like that? Why the hell do you want to route through a protocol built for in-person consumption? This is such a pointless overreach for the protocol. What would have been better is blessing a standardized pattern for exporting any MCP tool definition into a well-structured API endpoint. Then everything related to API endpoints like doc generation, comes along for free.
Instead we get this kitchen sink protocol that is going headlong toward polyfill hell, since no two IDEs support the same protocol features like structured content, local state, elicitations, etc., even from the same provider - Claude Code/Desktop/web all handle MCP connections differently. It's a shitshow.
Almost every major MCP service uses the same baseline default features (plain context) rather than build around partially-supported features. Why add more and more specs on the pile when adoption is so far behind?
The model has zero awareness of MCP, it’s the harness’ job to talk to the MCP server and simply present the model with the tools just like any other tool. The only giveaway to the model about where the tools come from is the ‘mcp__’ prefix in the name
Yep. I’ve found that having an endpoint that serves a well, documented openapi.yaml is very effective for agentic usage. The biggest difference is that you can break down a REST API into RPC-like chunks and save on some tokens if you break up the tools well. But pragmatically, I think saying “tell your agent to hit /api/v3/openapi.yaml” is quite useful
We did a prototype to integrate an agent into our application and basically just gave it a tool to discover the OpenAPI spec and call endpoints. It worked surprisingly well! One caveat was that some responses were too big and would poison the context, but then I gave the agent a GraalJS engine and allowed it to save responses and post-process them using JS. For the little amount of work required this gives the agent a lot of power without having to give it full CLI and without having to create bespoke tools.
The degree to which this idea has been overcomplicated is confusing. This could have been solved with some relatively simple patterns wrapped around HTTP and WebSockets (and if absolutely necessary, SSE).
> We’re starting a progressive discovery effort so a server can offer a small entry point and reveal more of its catalog as the conversation narrows.
Kind of late to the party. I've had to implement lazy loading of mcps in a couple of harnesses now but am moving to implement everything as code mode instead.
+1 for code mode. It's a game changer for runtime performance, flexibility of orchestrating lots of tool calls with complex logic, and all sorts of other goodies.
I'm in the process of switching all my personal stuff to a self-hosted fork of cloudflare-os right now. It's taking a lot of rearchitecting how my stuff works to fit within the cloudflare "no local files" paradigm, but for now I've got a container gatekeeper they can drive and they can check repos out in it.
My dream was for MCP to allow services like ours (cybersecurity) to provide a self documenting endpoint with authentication, and we just give users a URL and it just frikkin works. Instead from day 1 it’s been multiple standards as they pivoted, a context hungry feature, and feels like a kludge. That burned the idea of MCP for me and I’ve had such success with local tools and APIs that it’ll take a lot for me to go back.
Plus You're likely building an API already if you have an MCP. Not everyone using MCP is a dev, we have random corporate workers using our MCP. They don't know what an API is but they can add a plugin from an agent marketplace (which can also contain skills) and MCP is a bit narrower with a clear authorization system, tool discovery, and annotations (agents ask "confirm you want you want to write this").
Just give your end-users flexible options. If they have Claude Code then build more around the API side if needed.
Sometimes I really respect senior developers. When specs change, you obviously have to update existing work too. Looking at this MCP change, it seems like it's becoming stateless—I'm already wondering how to adapt.
Senior programmers always advised me to only use things that have been around for at least three years. Now I finally understand why.
At this point, I think 5 or even 10 years would be a more appropriate number (except for minor updates over things that have been around for a long time).
I clearly remember there was a time coffeescript looked really like the future of javascript.
Just curious, what kind of work have you done where this conceit feels valid in your mind? My career, at least, feels like an exception to this, but I guess its conceivable to me that it could be otherwise. You have had a lot managers push newer frameworks/technologies on you? Is this more VC startup land, or something else?
Maybe I'm old, but at least in web dev it doesn't feel that long ago that someone had to argue for, e.g., Vite over webpack, Svelte over React, etc..
Is there a way in MCP where I can "approve" certain privileged actions? Like imagine an MCP for buying stuff in Amazon but it can do everything including payment but is behind a gate that the human needs to approve
> With the 2026-07-28 release, a remote MCP server is now no different from any other HTTP workload
Good. Introducing a bespoke new protocol was one of the more bone-headed things MCP did on initial release.
It's unreal how bad the initial rollout was between HTTP/streaming and stdio, bearer auth and OAuth. Virtually every client/MCP server pair had a different portion of that matrix implemented.
The real disaster was making it stateful. Need to get some adults in the room.
Is stdio being deprecated? I couldn't tell from this page
The prose on the page is very unclear. My best interpretation is that they want to continue supporting stdio but that they don’t want it to be its own special protocol. The obvious way to do that would be to speak ordinary HTTP (version 1.1? 2?) over stdio and to use the MCP-over-HTTP protocol over the resulting HTTP transport.
This would be more complex to implement for a simple server, but it’s not exactly difficult.
Not everyone is on board with the idea of HTTP being the exclusive universal IPC bus.
I’m not really a fan. But if you’re building a protocol that needs to map to HTTP anyway, then maybe using the HTTP binding everywhere is not totally awful.
In the flip side: I’m currently designing an AI-adjacent protocol, and it will be able to map to WebTransport, but I don’t plan to define non-WebTransport HTTP bindings unless a very compelling reason appears. The main implementations will not use HTTP at all :)
> if you’re building a protocol that needs to map to HTTP anyway
I don't think there is any guarantee that HTTP will always be involved. For example I might be calling a local LLM via CLI/script on a server with a stdio MCP connector that just runs other CLI commands, and never sends any HTTP traffic.
Right. But there is a lot of real-world usage of MCP-over-HTTP-over-the-Internet, and a lot of “harnesses” want to support that use case, so they’re stuck either implementing the HTTP-based protocol or using a shim.
Would you prefer gRPC, thrift, avro, etc... ?
Those are mostly at a different layer. You can speak Thrift or Avro or Protobuf over stdio or HTTP or TCP or carrier pigeon.
gRPC spans layers, and it uses HTTP in a more intrusive way than even MCP does — it expects to own the entire URL space at the IP/port in question. Using gRPC in a nontrivial way for MCP would be fairly heavy-weight: you would probably need to set up reflection and figure out how to bind all the MCP calls to it unless you just use it as a tunnel.
grpc mcp is a thing... https://cloud.google.com/blog/products/networking/grpc-as-a-...
Wow, that looks like a huge mess.
I would prefer a core transport agnostic protocol, and then see MCP-over-HTTP being a spec on top of that.
Count me as not on board
I am very curious how many MCP servers will actually implement all of this:
"MCP authorization today is built around a person approving access in a browser. That works well for interactive clients, but more and more of the callers are agents running as cloud workloads with their own identity, acting on behalf of a user who isn’t present, or delegating narrower authority to sub-agents. We want MCP servers to have a standardized way to recognize and trust those agent identities, built on existing standards rather than pasted API keys and long-lived tokens.
The work here covers finalizing Demonstrating Proof of Possession (DPoP) and driving its adoption, and defining an opinionated path for agent identity and delegation through Workload Identity Federation, the ID-JAG grant behind Enterprise-Managed Authorization, and standard token exchange. We will also continue to grow our engagement with the OAuth standards bodies, including the IETF OAuth and WIMSE working groups, to help the underlying standards evolve with the building blocks that agent identity needs."
I think the spec overcomplicates everything honestly. Its not that hard to add a long running auth token and put it in the MCP config as a header to send along and then avoid all the extra special rules.
"Oh no it's a long lived token that's bad"
Put it in a secret manager like 1pw cli and now start an agent...
How does the agent auth with 1pw? How do you give it access to only the credentials it needs, with an approval flow and revocation? Who renews the token? You’ll likely end up reinventing something pretty close to what MCP is building towards.
Authn/authz is one of those things that can be really simple for pointed use cases but gets really complex when you need to support everything.
Quite a few options as of now:
https://www.1password.dev/get-started/secure-ai-access#secur...
https://1password.com/blog/1password-trusted-access-layer-fo...
Still far from perfect tho.
The perceived difficulty is not what is at play here. People and employers are not comfortable with the idea of long lived credentials to begin with -- and even less in the 'hands' of an AI agent.
The complexity in these protocols is mostly essential in nature (to the extent that you're not willing to totally reinvent the protocol, like AAuth).
That doesn't work well for enterprise-managed MCP, where you actually do want the user to overtly authorize their agent to user their identity for MCP services, rather than the MCP server just setting a user ID in an HTTP header somewhere and everyone hoping for the best.
Authorization for sub-entities is what is needed.
Having to define what an agent can do when it identifies on my behalf is cumbersome, especially when you start to get specialised agents.
Pattern based would be too easy for AI to game, but there's got to be a service independent way to limit permissions based on role.
I am Jack's right ear - awesome you get to hear stuff.
I am jack's right hand - great you get to input stuff.
I am Jack's synaesthesia.
What people who care about security want -- finely grained permissions that guarantee security boundaries, at the expense of bad UX
What most end users want -- for the machine to do what they want, as often as possible, while bothering them as little as possible
Windows' UAC journey is a microcosm of the space. The real long-term win is defining ground level permissions around common use cases, so that when composed they can alert as rarely as possible.
But that's an all-of-ecosystem change: the OS (providing usable boundaries), applications (updating to use minimal boundaries), and users (understanding what they'll need to approve/deny).
Hopefully quite a few.
I really love the idea of fully enabled agents and being able to cut down on human in the loop moments.
Things like https://projects.dev/ for example.
A ton of security problems and others to solve but it's still where I want the future of all this to go.
Why, directionally all of them. What they say is obviously true. Having to manually click things in the browser is a bottleneck and will be less and less acceptable for serious users.
And the individual work attached to making that transition will be done by agents.
agree. it seems there are two streams and they could diverge or converge?
1. workloads use existing credentials support RFC 7523 and OIDC discovery, 'trust the trust (credentials) which has already been established'. basically extend current dominant NHI paradigm.
2. DPoP mandate a signed proof for each request. so tie credential to a client-held key and specific request detail or context. viable to do at scale with #1, or does it diverge (e.g. because most #1 methods as most are not designed for DPoP?
It is viable. Think of workload identity federation as the mechanism for the client to get an bearer token initially, and DPoP as the mechanism for the client to present the access token to a resource server. Each DPoP proof is entirely self-contained, so resource servers don't need to manage any additional state. The only new state is the (usually ephemeral) private key held by the client:
1. Client generates a private/public keypair and uses it to generate DPoP Proofs - JWTs containing the entire public key embedded as a JWK within
2. Client presents credentials (WIF, client creds, auth code, etc.) to the Authorization Server along with a DPoP Proof
3. Authorization Server validates DPoP Proof and adds a claim to the access token containing the thumbprint - the SHA-256 hash - of the public JWK.
4. Resource Servers will now see the thumbprint claim and now know the access token needs to be presented with a fresh DPoP proof.
5. Clients generate fresh DPoP proofs and send them along with the access token
There are lots of additional details around nonces, timestamps, per-request binding, etc. but DPoP can be rolled out to any HTTP system that speaks Bearer token already.
I've been working on a protocol that promises all of that and more. We're currently targeting a NOSTR/Buzz demo in the coming week as a proof of concept.
Even now, the mcp server itself doesn't have to implement all of the possible security options. You can use something like agentgateway to act as an auth proxy for your mcp servers.
Such an example of overengineering, why not just use OAuth?
WIF works far better when you don’t want humans in the loop. For example, we’d do our development on cloud instances, those have identity linked to our humans via our IdP. Our IdP governs all access, for example: it lets devs use Datadog. If an agentic workflow needs Datadog access and the MCP requests OAuth that slows the loop down. At the same time, we don’t want Service Accounts everywhere because we need to be able to answer “who” a lot for compliance reasons.
Oauth assumes interactivity
I still struggle to see how a MCP endpoint is easier for agents to work with compared with a REST endpoint and a skills.md file.
it's not easier for agents to work with. it's easier for organizations to work with.
for agents, they're essentially the same thing - remote endpoints, and instructions on how to call those endpoints. what MCP brings is centralized updating and distribution of the instructions, and a promise that the skill and the REST api won't be out of sync with each other.
the one thing that skill.md+REST doesn't solve is how you get that skill.md to somebody else's computer, and how you ship an update to somebody else's computer once they've got a copy of the skill. if that's a problem you need to solve, you can either start inventing skill.md distribution protocols, or you can just use MCP.
> it's easier for organizations to work with.
I can see that.
I am developing my first custom agents. I am finding that if I offload some workflow to another agent (e.g. Claude Code), the simplest way to control what it can or cannot do is via an MCP server (which only lets it access tools that I develop/approve myself). I do need that control in the corporate environment.
Maybe there are easier ways to do it, just learning and exploring now.
No need to invent skill.md distribution protocols. Use `/.well-known/agent-skills/index.json` -- see https://github.com/agentskills/agentskills/pull/254.
It's already in use in several places (e.g., https://www.mintlify.com/docs/ai/skillmd#skills-discovery-en...) and is supported by `npx skills add`.
Maybe I just need more patience, but I took a look at some tools that have MCPs, and their "setup guide" on how to start using the MCP server really gave me brain damage. Is this really easier to work with?
For antiquated "enterprise" APIs that were already a mess of legacy cruft, yes. MCP forced vendors to reconsider the ergonomics of their interface.
It seems like organizations will mostly want remote access via http and the other flavors of MCP aren’t so useful? Although, I suppose if you install an app locally, it might have an MCP interface.
I guess it's similar to SOAP, it was usually over HTTP but sometimes the alternatives were used (eg. email [1])
[1]: https://www.w3.org/TR/soap12-email/
That would be /llms.txt https://llmstxt.org/
How is distributing a markdown file the bottleneck?
It is the automatic distribution and automatic update. The questions isn't "how does one download a text file to another persons computer?". It is "how does someone with a skill.md file on their computer discover that a new version of that file is available".
This isn't a "bottleneck" but rather a capability (or lack thereof). As you add more and more capabilities, especially ones relevant to enterprise situations like authentication, authorization, governance, etc. then MCP starts to pay off.
If you do not need those capabilities, then you do not need MCP. And then you shouldn't use it. But if you do need those capabilities then it might be worth using MCP rather than inventing your own way to do them.
I see. In my head it would be something like the agents harness having a list of services it interacts with, reaches out to service.com/agents.md for a fresh copy every so often and uses that to resolve the relevant tool calls.
Valid. There are many ways to do it.
But for enterprise there may be teams, each developing their own way to do it. Then there will be many different ways that it is done throughout the enterprise, which is hard re: governance. Better/easier to adhere to an industry standard which can be audited, especially for enterprises where that is a legal requirement.
That isn't a reason you should use it, just an explanation about why someone has to use it.
>reaches out to service.com/agents.md for a fresh copy every so often and uses that to resolve the relevant tool calls.
that is basically what MCP is. except it answers all the questions that your version handwaves away - how often do you get a fresh copy, how do you describe the relevant tool calls, how are the tools organized, and how does auth work.
If that truly is the main selling point - it seems like a shallow moat versus skills + rest..
Because it’s something else that’s non-standard between providers.
Not all agents have access to a sandbox/cli/code execution environment to run arbitrary api calls etc. MCP helps by essentially having another tool call without needing a sandbox. If you do have a sandbox, then might as well do codemode if you insist on mcp https://blog.cloudflare.com/code-mode/
Because it's a separate marketing term.
Instead of the CEO mandating that the API server has to be agent compatible (where who knows what that means), they can just say "our product has an MCP".
On a technical level, who knows what it actually is (is it actually the new stateless version, does it have all the endpoints, is the regular API more feature-rich, do I need those features for my workflow?, etc.). But at a surface-level, the intention is clearer, and lets other gears (like sales and marketing) keep spinning without getting bogged down in technical details.
All that, yes. And at a technical level, it is much easier to have a single spec to follow. When a customer complains that their client isn't working, I can point at how they aren't following OAuth discovery properly or something.
It's determinism, flexibility, and language.
To the LLM, the a skill input is deterministic, inflexible, and outputs natural language.
A REST API (not the REST itself, but modern output being JSON primitives) outputs are deterministic, flexible, but doesn't output natural language.
An MCP as an input is deterministic, flexible, outputs natural language.
Then we ask the same question on whether the LLM gets back a response that is deterministic. Skills output are not deterministic, it requires LLM to generate tokens to take action. It may or may not take the specific actions instructed by the skill.
So, Skills + REST API = MCP only if you can deterministically call on the REST API.
In other words:
* /skill may or may not call on the instructed action
* /tool (or @tool) will guarantee the action is taken
This is overgeneralizing and we need to talk about harness-specific features like hooks (which adds a deterministic action to skill usage).
At my company Parallel AI, I just built an extremely well documented openapi spec and then MCP builds from that. Complete alignment with UI/API/MCP so there is no extra work.
Are others doing this?
It seemed obvious to me, but I don't hear others saying it.
The challenge with this is that it often causes a proliferation of MCP tools which bloats context, which is one of the reasons that MCP was created.
Oh sorry I didn't explain that we are not dumping the entire endpoint list to the MCP. We have 400+ endpoints so this would be terrible.
We tag each endpoint by category in the OpenAPI spec and require the MCP to request actions by tag and optional query term. At most we return 10 endpoints at a time and the LLM can request more using pagination.
These tags also create your categories in API doc websites like swagger/mintlify so its a win win.
OpenAPI spec is the single source of truth.
I created MCP AQL, which is an extension to the MCP spec, specifically to reduce the bloat for MCP tools.
It only has five CRUDE endpoint: Create, Read, Update, Delete, and Execute using a GraphQL-like structure for tool calling of the operations within the endpoints. It's very efficient, and robust. there's all kinds of exemplar tools and components to make adapters for any MCP server. You don't even need to rewrite your own MCP server. Just create an adapter for it.
All open source at MCPAQL.com
Just because a MCP server offers 100 MCP tools doesn't mean that they all have to be in your context. Any decent harness will let you filter out ones you don't want. And to take that concept further you really should be designing specialized subagents that only have access to a small subset of total MCP tools in the first place.
Yes, for .NET and Java backend stuff, it is basically extending what is already there.
On low code/no code tools, you get additional metadata for webhooks.
Companies got to release an MCP server for their product and tell their investors they were pivoting to be AI native.
I work on an MCP server and I agree. There is no need to make MCP servers the gateway for agentic or programmatic integration - that's exactly what API servers handle out of the box. The value of MCP servers is fine-toothed access on a tool-by-tool basis and leaving output digestion to the LLM.
LLMs do GREAT utilizing well-defined tools to accomplish tasks. Look at Datadog's MCP, instead of figuring out a multitude of filter and navigation options your LLM can immediately navigate to what you want and extract the precise data you need. Tool instructions with defined I/O structures let LLMs fly.
But for a nightly cron job pulling down stats or something like that? Why the hell do you want to route through a protocol built for in-person consumption? This is such a pointless overreach for the protocol. What would have been better is blessing a standardized pattern for exporting any MCP tool definition into a well-structured API endpoint. Then everything related to API endpoints like doc generation, comes along for free.
Instead we get this kitchen sink protocol that is going headlong toward polyfill hell, since no two IDEs support the same protocol features like structured content, local state, elicitations, etc., even from the same provider - Claude Code/Desktop/web all handle MCP connections differently. It's a shitshow.
Almost every major MCP service uses the same baseline default features (plain context) rather than build around partially-supported features. Why add more and more specs on the pile when adoption is so far behind?
The model has zero awareness of MCP, it’s the harness’ job to talk to the MCP server and simply present the model with the tools just like any other tool. The only giveaway to the model about where the tools come from is the ‘mcp__’ prefix in the name
Yep. I’ve found that having an endpoint that serves a well, documented openapi.yaml is very effective for agentic usage. The biggest difference is that you can break down a REST API into RPC-like chunks and save on some tokens if you break up the tools well. But pragmatically, I think saying “tell your agent to hit /api/v3/openapi.yaml” is quite useful
We did a prototype to integrate an agent into our application and basically just gave it a tool to discover the OpenAPI spec and call endpoints. It worked surprisingly well! One caveat was that some responses were too big and would poison the context, but then I gave the agent a GraalJS engine and allowed it to save responses and post-process them using JS. For the little amount of work required this gives the agent a lot of power without having to give it full CLI and without having to create bespoke tools.
MCP can also handle authorization, since you don't want to put your password to skills.md and send it to China
Mcp predates skills - and has a more granular permission model then skills + bash commands.
I don't want to expose my API key to Claude. An stdio MCP server wrapping an API lets me hide it
wtf is the difference when 1) you put a key in front of the mcp 2) you mcp a whole bunch of privileged access.
it's like saying "i don't want to give Claude access to my file system but i'm fine letting it run bash" ......
The difference is that the LLM never sees your keys/secrets. My understanding is that can make a big difference.
Does mcp guarantee that, per se?
Not if you assume the straw man like grandparent, but yes if you use it thoughtfully.
easier to gate MCP tools? you can allow/deny tools very easily
or a CLI
CLI don't work in cloud environments like MACH architecture.
Plus why spawning processes all the time.
This is the strongest argument I've seen against CLI for LLMs. Thank you.
Me too, it is just another RPC endpoint, heck all of this kind of stuff could even be done with Sun RPC.
Why not just give the model a prompt?
Every gain in LLMs is either through increases in compute efficiency, Architecture or Harnesses...
The rest seems like bells and whistles
The degree to which this idea has been overcomplicated is confusing. This could have been solved with some relatively simple patterns wrapped around HTTP and WebSockets (and if absolutely necessary, SSE).
When I see "MCP" I still translate that to Master Control Program.
And here I thought I was old.
> We’re starting a progressive discovery effort so a server can offer a small entry point and reveal more of its catalog as the conversation narrows.
Kind of late to the party. I've had to implement lazy loading of mcps in a couple of harnesses now but am moving to implement everything as code mode instead.
+1 for code mode. It's a game changer for runtime performance, flexibility of orchestrating lots of tool calls with complex logic, and all sorts of other goodies.
I'm in the process of switching all my personal stuff to a self-hosted fork of cloudflare-os right now. It's taking a lot of rearchitecting how my stuff works to fit within the cloudflare "no local files" paradigm, but for now I've got a container gatekeeper they can drive and they can check repos out in it.
What do you mean "as code mode"?
Basically https://blog.cloudflare.com/code-mode/
I was getting fed up with AWS mcp telling me it is eol.
[delayed]
My dream was for MCP to allow services like ours (cybersecurity) to provide a self documenting endpoint with authentication, and we just give users a URL and it just frikkin works. Instead from day 1 it’s been multiple standards as they pivoted, a context hungry feature, and feels like a kludge. That burned the idea of MCP for me and I’ve had such success with local tools and APIs that it’ll take a lot for me to go back.
I mean… so just HTTP + OpenAPI spec?
It actually doesn’t matter. Pick your favorite way of giving a dev access to capability on a remote server.
Plus You're likely building an API already if you have an MCP. Not everyone using MCP is a dev, we have random corporate workers using our MCP. They don't know what an API is but they can add a plugin from an agent marketplace (which can also contain skills) and MCP is a bit narrower with a clear authorization system, tool discovery, and annotations (agents ask "confirm you want you want to write this").
Just give your end-users flexible options. If they have Claude Code then build more around the API side if needed.
In v.1 making MCP stateful was such a deployment-unfriendly way to do it - you need a complicated persistence layer for it to work.
All while it is just a fancy way make your OpenSchema PAI visible to AI.
I think MCP is jumping some sharks here.
Nobody needs to have every functionality of HTTP offloaded to MCP at all, at this point.
I'll stick to the bare minimum that works.
Agree 100%, the elegance of JSON-RPC is a virtue.
This reminds me of the actor model[1]
[1] https://doc.akka.io/libraries/akka-core/current/typed/actors...
Half the battle is just knowing this exists
Sometimes I really respect senior developers. When specs change, you obviously have to update existing work too. Looking at this MCP change, it seems like it's becoming stateless—I'm already wondering how to adapt.
Senior programmers always advised me to only use things that have been around for at least three years. Now I finally understand why.
At this point, I think 5 or even 10 years would be a more appropriate number (except for minor updates over things that have been around for a long time).
I clearly remember there was a time coffeescript looked really like the future of javascript.
> "only use things that have been around for at least three years"
Yikes. I can understand the desire to mitigate churn, but following this advice would be career suicide. Trying new things is essential.
Keeping up with changes is valuable.
At the same time, it's often smart to avoid putting things into production that haven't matured or demonstrated staying power.
Or, to badly mangle Postel's law:
Be liberal in what you learn, and conservative in what you deploy
Just curious, what kind of work have you done where this conceit feels valid in your mind? My career, at least, feels like an exception to this, but I guess its conceivable to me that it could be otherwise. You have had a lot managers push newer frameworks/technologies on you? Is this more VC startup land, or something else?
Maybe I'm old, but at least in web dev it doesn't feel that long ago that someone had to argue for, e.g., Vite over webpack, Svelte over React, etc..
Depends on the thing.
I had to give maintenance to things people deployed to pad their resumes with "shiny new thing", and it was not fun.
If you intend to deploy and leave that as legacy for some poor shlemiel, sure.
If you intend to stay and actually keep things running, it's much better to use tried and tested stuff.
Three years is nothing, what kind of work do you do where you need something released in the last three years?
And I’m not OP, but I would assume the senior developers made a distinction between try and use.
Truth doesn't move much. It moves slowly, so that those holding onto it don't fall. Keep up.
Is there a way in MCP where I can "approve" certain privileged actions? Like imagine an MCP for buying stuff in Amazon but it can do everything including payment but is behind a gate that the human needs to approve