describe_tool

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

No annotations are present, so the description carries the burden. It adds 'FREE' to signal no cost, and clarifies the return content (full description and input schema). However, it does not disclose error behavior for unknown names, case sensitivity, or whether authentication is required, which are relevant for robust agent selection.

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 two short phrases plus an example, with the action verb and resource front-loaded. 'FREE' and the example are high-signal and not redundant. Zero wasted words.

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 single-parameter metadata-lookup tool with no output schema, the description gives the action, the input source and format, and an example. It omits error cases and return formatting, but the tool's simplicity makes these minor. The lack of annotations and output schema is only partially compensated by the 'FREE' note and example.

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 provides only `name: string` with 0% description coverage, so the description must compensate. It adds that the name must be exact and gives its source (search_tools), plus a concrete example `{name:'pdf_merge'}`. This is enough to correctly populate the parameter.

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?

Description states 'Get one tool's full description and input schema by exact name'—a specific verb, resource, and method. The example and reference to search_tools differentiate it from sibling search_tools, which is for finding tool names, while describe_tool retrieves full details for one exact name.

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 'by exact name (as returned by search_tools)' tells the agent to first discover names via search_tools and then call describe_tool with that name. It implies that search_tools is the alternative when names are unknown, and provides an example usage. Does not explicitly list exclusion conditions, but for a trivial lookup tool the guidance is sufficient.

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