Retrieve the full description and input schema of any tool before calling it, so you can pass valid parameters and avoid errors.
Show one tool's full description and input schema before calling it
| Name | Required | Description | Default |
|---|---|---|---|
| tool_name | Yes | Exact registered tool name | |
| response_format | No | 'concise' = human prose, 'detailed' = more fields in prose, 'json' = raw API object | concise |
Changes observed during successful MCP inspections.
v1.28.0Input schema / properties / response_formatAdded value: +{
+ "default": "concise",
+ "description": "'concise' = human prose, 'detailed' = more fields in prose, 'json' = raw API object",
+ "enum": [
+ "concise",
+ "detailed",
+ "json"
+ ],
+ "type": "string"
+}v1.26.1Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full burden of explaining behavior. It clearly conveys that the tool is read-only introspection ('Show'), but it does not explicitly state that it has no side effects, does not invoke the target tool, or what happens for invalid tool names. These are minor gaps for a simple inspection tool.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is a single, front-loaded sentence with zero filler. Every word earns its place, and the core action is immediately clear.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a simple introspection tool, the description plus the complete input schema covers what an agent needs to call it correctly. It does not describe output beyond what the response_format enum implies, but that is largely self-explanatory. Minor missing context includes error behavior for unknown tool names.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 100%, so the schema already documents both parameters and their meanings. The description adds no extra parameter-level detail, but that is acceptable given the schema's completeness. The response_format enum is fully described in the schema.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the tool's function: showing a single tool's full description and input schema. It uses a specific verb and resource, and the 'before calling it' phrasing adds intent. However, it does not explicitly distinguish itself from sibling meta-tools like find_tool or toolset_report.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The phrase 'before calling it' implies when to use the tool: prior to invoking another tool. But there is no explicit guidance about when not to use it, no mention of alternatives, and no indication of how it differs from other inspection or discovery tools.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.