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

With no annotations, the description carries the full burden. It explicitly discloses that the call is free (no credit) and needs no API key, addressing cost and auth. It also states what is returned: a list of templates, each with id and fields. This is sufficient for a read-only list operation, though it does not detail pagination or ordering, which are minor for this simple 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?

Two sentences, no fluff. The first sentence front-loads the core purpose and result, the second adds cost and auth details. Every word earns its place, and the description is appropriately sized for a tool with zero parameters.

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 zero-parameter, no-output-schema tool, the description is complete. It specifies what is returned (id and fields), how it is used (passed to parse_document as schema_id), and the cost/auth implications. There is no ambiguity about calling it correctly. The only minor omission is whether the list is exhaustive, but that is not critical for an agent's decision.

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?

The tool has zero parameters, so the baseline is 4. The description adds value by clarifying that the returned schema ids are meant to be passed as schema_id to parse_document, which is not in the schema itself. Since there are no parameters, the description's role in parameter semantics is limited but still fulfills the baseline.

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 purpose: to return built-in schema templates for parse_document. It specifies the resource (schema templates), the target use (as schema_id), and provides concrete examples (invoice, receipt, resume). This unambiguously distinguishes it from sibling tools like parse_document (which parses) and infer_schema (which creates custom schemas).

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 description implies when to use it: before calling parse_document with a schema_id, you need to know available templates. It also notes that it is free and requires no API key, which is useful context. However, it does not explicitly contrast with alternatives like infer_schema for custom schemas or validate, so the guidance is implied rather than explicit.

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