Agent Data Tools

tool_details

Read-onlyIdempotent

Fetches a named tool's invocation details—inputs, required fields, examples, pricing, and response shape—so agents can call it correctly.

Instructions

Everything needed to call one tool: what it does, every input with its type, whether it is required and an example value, the price per successful call (and the lower price with a prepaid key where there is one), whether it is in the free calls, an example call and the shape of its answer. Free. Take the name from find_tool.

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": {
      "name": "<name>"
    },
    "name": "tool_details"
  }
}

Input Schema

Name	Required	Description	Default
`name`	Yes	The tool's name from find_tool, for example weather_forecast

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.3.0Nov 14, 2026

TDQS

A3.9/5.0

Behavior4/5

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

Beyond the readOnly/idempotent/non-destructive annotations, the description discloses cost behavior ('Free') and that the payload includes pricing per successful call plus any lower prepaid-key price and free-call eligibility — commercially relevant context the annotations cannot convey. It does not say what happens when the name is unknown or invalid, which is the one behavioral gap.

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?

One front-loaded sentence with a dense but well-ordered enumeration of what is returned, ending on the actionable instruction. It is slightly run-on and repeats 'example' twice, but no sentence is wasted.

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?

With no output schema, the description correctly carries the burden of describing the response shape (fields, pricing, example call, answer structure), which is exactly what an agent needs. Missing only error/invalid-name behavior and an explicit handoff to call_tool.

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 100% and the single 'name' property already documents itself as coming from find_tool with an example. The description's 'Take the name from find_tool' reinforces provenance but adds no format, constraint, or resolution semantics beyond the schema, so the baseline 3 applies.

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?

The opening clause 'Everything needed to call one tool' plus the enumeration of returned fields (inputs, types, required flags, price, example call, answer shape) makes clear this is a per-tool metadata/pricing lookup rather than an invocation. It is distinguishable from call_tool by its emphasis on describing rather than executing, though it never names call_tool explicitly to sharpen the contrast.

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?

The final instruction 'Take the name from find_tool' supplies a concrete prerequisite and tells the agent which sibling produces the required argument. It stops short of stating when not to use this tool or explicitly routing execution to call_tool, so the workflow is clear but not fully closed.

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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