MCP vs Function Calling: When You Actually Need a Server
They are not competing ways to give a model tools. One is the engine; the other is a distribution standard wrapped around it — and you pay for the wrapper in tokens and attack surface.
5 min
MCP vs REST: Do Your Agents Need a Protocol, or Just Your API?
Most MCP servers are REST APIs underneath. The honest question isn't which transport to use — it's how much of your API to expose, and the data says the answer is about a fifth of it.
4 min
MCP Tools vs Resources vs Prompts: The Three Lanes, and Why Only One Got Paved
The Model Context Protocol defines three server primitives split by who's in control — the model, the app, the user. The ecosystem implemented one of them.
5 min
How to Build an MCP Server: A Practical Guide for Agent Developers
The protocol everyone adopted in 2025 is simpler to build for than the hype suggests — but the part that decides whether your server works isn't the code.
5 min
Your Agent Is Now an MCP Server: What Exposing an Agent as a Tool Quietly Throws Away
Deploy a LangGraph agent and it auto-publishes a /mcp endpoint, so any client can call it as a tool. Convenient — and lossy. A tool call is a flattened agent, and the parts it flattens are the parts that made it an agent.
4 min
LangGraph Platform Is Now LangSmith Deployment — and Your Agent Ships as an MCP Server by Default
The rename reads like marketing housekeeping. It isn't. Folding deploy into LangSmith and handing every deployed agent an MCP endpoint quietly reclassifies your agent from an application into a tool other agents can call.
4 min
Stainless Is Winding Down: Where to Generate SDKs and MCP Servers Now
The two best independent SDK generators got bought in 2026 — Fern by Postman, Stainless by Anthropic, which is retiring its shared generator. The layer that turns an API into agent-usable tools stopped being neutral infrastructure.
4 min
MCP Transports: stdio vs SSE vs Streamable HTTP
The Model Context Protocol replaced its HTTP+SSE transport with Streamable HTTP in 2025. Choosing it does not make your server serverless-friendly — and the reason is the part nobody reads.
5 min
MCP Goes Stateless: What the 2026-07-28 Spec Changes for Agent Builders
The biggest Model Context Protocol revision since launch deletes the session, the handshake, and even the client-side LLM call. The headline isn't new features — it's that the protocol got smaller.
5 min
MCP Caching Explained: ttlMs, cacheScope, and the One Word That Leaks User Data
The 2026-07-28 spec lets an MCP server tell clients how long a result stays fresh and whether it's safe to share. One of those two fields is a performance knob. The other is a security boundary people will read as a performance knob.
5 min
Tracing MCP Tool Calls Without Sessions: Why traceparent Became the Correlation ID
MCP's 2026-07-28 spec deletes the session handshake that ops teams quietly used to stitch an agent's tool calls together in their logs. The replacement is W3C Trace Context — and it doesn't do the same job.
5 min
How to Resume an Agent's Stream After the Connection Drops
Durable execution saves the agent's work when the server dies. It does nothing for the user whose phone dropped Wi-Fi mid-answer — that's a different resume problem, on the other side of the wire, and the new stateless MCP spec quietly made it harder.
4 min
MCP Finally Has a Deprecation Policy: A 12-Month Guarantee That Stops at the Core
The 2026-07-28 spec's quietest change is the one that decides whether you can build a business on MCP — a formal feature lifecycle with a year of runway. The catch is where the guarantee ends.
4 min
Versioning an AI Agent's Tools: Schema Evolution and the Regression a Validator Can't Catch
You can change a tool's schema in a fully backward-compatible way and still break your agent. The contract has two consumers that version differently — your code, which you can pin, and the model, which you can't.
5 min
MCP Server Cards: How an Agent Will Vet a Server Before It Connects
A new .well-known discovery file lets clients read an MCP server's identity, transport, and auth requirements without a handshake — and it pointedly refuses to list the tools.
5 min
The Official MCP Registry, Explained: How to Publish and Find MCP Servers
The official MCP Registry isn't an app store — it's a canonical metadata feed built to prove who owns a server name, and it leaves search and curation to everyone downstream.
5 min
Agent Registry vs MCP Registry: The New Discovery Layer, and Why It's Already Fragmenting
The MCP registry catalogs tools. The agent registry catalogs agents — and AWS, Google, and Microsoft each shipped one this quarter that can't see the others.
3 min
Agentic Resource Discovery (ARD): The Search Layer That Sits in Front of MCP and A2A
Eleven vendors just agreed on how agents find tools across the open web. The interesting part is what ARD refuses to be — not a protocol, not a registry of record, just the step before invocation.
5 min
How MCP Servers Actually Ship: The Registry Is a Phone Book, OCI Is the Supply Chain
The official MCP registry deliberately refuses to host code — so the hard part, trust, lands wherever the artifact lives. Docker's answer is to make that place an OCI image.
4 min
Dynamic Tool Management for Multi-Turn Agents: Only Reasoning Models Can Prune Their Own Toolset
Loading the right MCP tools on demand is a solved problem. Removing the wrong ones over a long conversation is not — and a new benchmark finds that letting the agent do it itself only works if the model reasons.
5 min
How to Handle a Tool Result Too Large for the Context Window: Truncate, Paginate, or Hand Back a Handle
The overflow that kills agents happens at the one boundary the MCP spec never paginated — the tool result. And the reflex fix, truncating to N characters, is the only option that's strictly worse than doing nothing.
5 min
How Many Tools Should an AI Agent Have? Your Retriever's Recall Can't Tell You
Retrieve 100 tools and the right one is 'in the list' 99% of the time — the same odds a random shortlist gives you. Two 2026 papers show why recall is the wrong number, and why fewer tools win.
5 min
The Tool Bill: Why Agent Cost Tracking Is Moving to the MCP Gateway
LiteLLM v1.91.0 quietly started rolling MCP tool-call spend into the same user counters that meter tokens. It's a small line in the changelog and a large move on the board — the half of the agent bill token meters never saw.
5 min
MCP Authorization Explained: OAuth 2.1, Resource Indicators, and the Confused Deputy
Between two spec revisions in 2025, MCP servers quietly stopped being their own authorization servers. The one parameter that change forces your client to send is the whole security story.
6 min
X's Hosted MCP Server Reads Everything and Posts Nothing
X now runs an official Model Context Protocol server at api.x.com/mcp so agents can search posts, look up users, and read trends through your own login — but it will not let them post. The asymmetry is the whole design.
4 min
MCP Tool Annotations, Explained: What readOnlyHint, destructiveHint, and idempotentHint Actually Guarantee
The four booleans on an MCP tool look like a permission model. They aren't — they're a risk vocabulary for trusted servers, and wiring them into auto-approval is the mistake.
5 min
MCP Apps, Explained: How Servers Render Interactive UIs in Sandboxed Iframes
The 2026-07-28 spec ships MCP Apps as an official extension. The sandboxed iframe everyone points to is not the security boundary — the consent path is, and that changes what you should actually worry about.
5 min
The Confused Deputy Problem in MCP: Why Agent Auth Keeps Failing the Same Way
A 1988 access-control bug is the shape of 2026's worst MCP breaches. Understanding the confused deputy tells you why 'just add OAuth' doesn't fix your agent — and what the spec actually changed.
5 min
The OWASP MCP Top 10, Explained: A Security Checklist for Tool-Connected Agents
OWASP now has a third Top 10 — one scoped to a single protocol. The surprise isn't a new class of AI attack; it's that connecting an agent to MCP servers re-exposes 2010-era web and supply-chain bugs through a channel that auto-executes them.
6 min
MCP-Bench vs MCPToolBench++ vs MCPAgentBench: How to Benchmark an Agent's MCP Tool Use
Function-calling leaderboards test a model against a handful of curated tools. A real MCP host hands it thousands — and that is a different benchmark, with a different failure mode.
4 min
Who Controls MCP Now? Inside the Agentic AI Foundation
For a year the question that stalled enterprise bets on MCP was 'what happens when Anthropic changes its mind?' In December that question got an answer — and the answer reveals what the standards war was really about.
5 min