Protocol-decoded view
Tool calls, resource reads, and prompt responses are rendered as first-class objects.
MCP Protocol Debugger
A protocol-aware debugger for MCP sessions.
Inspect tool list negotiation, request/response framing, and session state — without piping JSON-RPC into a terminal.
No credit card required · Free plan available
MCP Session Inspectorsess_91b4 · CONNECTED
Tool registry
refunds.create
orders.list
replay.run
incidents.open
Capabilities
tools, resources
→ tools/call
{ "name": "refunds.create" }
← tools/result
{ "ok": true, "id": "re_3b" }
→ resources/read
{ "uri": "memory://refund-policy" }
← error
{ "code": -32601, "message": "method not found" }
What you actually get
The MCP Debugger speaks the Model Context Protocol natively. Capture a live session, pin a session ID, and watch every tool registration, resource fetch, prompt response, and lifecycle event arrive with proper protocol decoding. No more squinting at hex frames or correlating IDs by hand.
- Native JSON-RPC framing with method-aware rendering
- Pinned session view with live state diffing
- Replay any session against a new MCP server build
- Surfaces protocol-level errors that generic debuggers miss
Why it matters
Built for the moments where minutes turn into hours.
Session state inspector
See the live tool registry, capability set, and outstanding request map at any instant.
Reproducible sessions
Save a session, replay it against a new server build, and diff the responses.
Use cases
What teams ship with this.
Real situations where mcp debugger replaces an afternoon of detective work with a single, decisive answer.
- 01
Verify a new MCP server returns the expected tool list before customer rollout.
- 02
Reproduce a flaky tool call by replaying its exact session prefix.
- 03
Confirm an agent honors capability negotiation and rejects unsupported tools.
Pairs well with
More of the WebhookScout platform
Set up in under a minute
Ship mcp debugger this afternoon.
Start free, capture a live endpoint in seconds, and put the whole WebhookScout platform behind your integrations.