peerkith-mcp

spend_demo

Simulate a card spend with cap token; returns spent:true for allowed demo checks or spent:false/isError when denied, no real money moved. Get token via cap_preflight or cap_check first.

Instructions

Week-2 demo spend hop: POST /spend-demo with card + action:spend + cap_token (+ optional amount_note string). Deny → isError / spent:false, no hop. Allow → spent:true demo only (no money). Get token via cap_preflight/cap_check first.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "cap_token": "<cap_token>"
    },
    "name": "spend_demo"
  }
}

Input Schema

Name	Required	Description	Default
`card`	No
`cap_token`	Yes
`amount_note`	No

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.5.1Oct 1, 2026

TDQS

A3.9/5.0

Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the full burden and does disclose both outcomes: deny yields isError/spent:false with no hop, allow yields spent:true with an explicit 'no money' caveat. It adds real behavioral context (error signalling, non-financial side effect) though it omits any auth/permission or idempotency notes.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Tight and front-loaded: the endpoint, payload, and outcome branch are stated in two dense sentences plus the prerequisite. Arrow notation is efficient, though the 'Week-2 demo hop' framing is slightly opaque padding.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a no-annotation, no-output-schema tool with three params, the description covers the prerequisite, the payload contract, and both success/failure returns. It is complete enough to invoke correctly, lacking only detail on the 'card' identifier semantics.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 0%, so the description must compensate. It names all three params but only adds genuine meaning for cap_token (obtained from cap_preflight/cap_check) while 'card' and 'optional amount_note string' merely restate the schema without clarifying formats or accepted values.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

States the action (a demo spend via POST /spend-demo) and the payload shape (card + action:spend + cap_token). It also clearly distinguishes scope from siblings by naming cap_preflight/cap_check as the token source, though the term 'hop' is private jargon that adds little for an outside agent.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives an explicit prerequisite sequence ('Get token via cap_preflight/cap_check first') and names those alternatives. It stops short of stating when a caller should prefer this demo over other spend paths, but the sequencing guidance is concrete.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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