Testing & Playground

protomcp includes built-in testing — no agent, no MCP client configuration, no external tools.

pmcp test — CLI

List everything

pmcp test server.py list

Shows all tools with parameter schemas, resources with URIs and MIME types, and prompts with arguments:

Tools (3):
  add — Add two numbers
    a (integer, required)
    b (integer, required)

  search_notes — Search meeting notes
    query (string, required)

Resources (1):
  notes://index — List of available notes  [application/json]

Prompts (1):
  summarize_note — Summarize a meeting note
    note_id (required) — ID of the note
    style (optional) — Summary style

Call a tool

pmcp test server.py call add --args '{"a": 2, "b": 3}'

Shows the result, timing, and the full protocol trace:

Tool: add
Duration: 1ms
Status: ok

Result:
  5

Trace (5 messages):
  [10:15:32.100] send initialize
  [10:15:32.101] recv
  [10:15:32.101] send notifications/initialized
  [10:15:32.101] send tools/call
  [10:15:32.102] recv

Tool list changes

If a tool call enables or disables other tools, the output shows it:

pmcp test server.py call login --args '{"token": "valid"}'

Tools enabled: [create_record, delete_record]
Tools disabled: [login]

Flags

Flag	Default	Description
--args '{...}'	{}	JSON arguments for call
--format json	text	Machine-readable JSON output
--trace=false	true	Suppress protocol trace

JSON output

pmcp test server.py list --format json
pmcp test server.py call add --args '{"a":1,"b":2}' --format json

Outputs structured JSON — useful for CI or scripting.

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pmcp playground — Interactive web UI

pmcp playground server.py --port 3000

Opens a web-based testing environment at http://localhost:3000.

Two-panel layout

Left panel — Interaction:

• Browse tools, resources, and prompts in tabbed view
• Auto-generated forms from your JSON schemas
• Call tools, read resources, get prompts with one click
• Interaction history shows results like a chat

Right panel — Protocol trace:

• Every JSON-RPC message in both directions, timestamped
• Color-coded: blue (outgoing), green (incoming), yellow (notifications)
• Click any entry to expand the full JSON-RPC message
• Auto-scrolls to latest unless you scroll up to inspect

Live features

• Hot reload: save your file and the playground updates automatically
• Tool list changes: when a tool call enables/disables tools, you see it happen in real-time
• Connection status: green dot when connected, red when disconnected

Flags

Flag	Default	Description
--port	8080	Port to serve on
--host	localhost	Address to bind