describe_tool
Describe a catalog or MCP tool, its availability, inputs, HTTP route and the MCP entry point.
Input Schema
| Name | Required | Description | Default |
|---|---|---|---|
| toolId | Yes | Catalog tool ID or MCP tool name. |
Describe a catalog or MCP tool, its availability, inputs, HTTP route and the MCP entry point.
| Name | Required | Description | Default |
|---|---|---|---|
| toolId | Yes | Catalog tool ID or MCP tool name. |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered. The description adds useful content about what the response contains, but says nothing about behavior when the ID is unknown or invalid, which matters for a lookup 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?
A single dense sentence with the action front-loaded and zero filler. The trailing list of returned fields is compact and earns its place, though the comma run-on is slightly harder to parse than a structured list.
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?
With no output schema, the description correctly compensates by naming the fields returned, which is the right move. However it leaves ambiguous what 'availability' means, omits the missing/unknown-tool case, and does not cover how to obtain a valid toolId, so a lookup tool of this kind is only adequately served.
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?
There is a single parameter with 100% schema description coverage ('Catalog tool ID or MCP tool name'), so the schema does the heavy lifting. The description never mentions the parameter and adds no format, case-sensitivity, or ID-resolution detail beyond 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 gives a specific verb ('Describe') and resource ('a catalog or MCP tool') and enumerates the fields returned (availability, inputs, HTTP route, MCP entry point), so an agent can distinguish it from list_tools or run_tool. It stops short of explicitly naming those siblings as alternatives.
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?
Usage is only implied: you call it when you need details about a tool you already have an ID for. There is no guidance on where the toolId comes from (e.g., list_tools/search_tools) and no stated when-not-to-use or alternative for executing versus inspecting.
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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