get_api_schema

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

With no annotations supplied, the description carries the burden and does real work: it discloses that cross-references are returned as "#/components/schemas/<Name>" placeholders and enumerated in referencedSchemas, which tells the agent how to follow up. It does not mention auth, rate limits, or whether search and name can be combined, but for a read-only reference lookup those gaps are modest.

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?

Three sentences, each earning its place: what it is, how to use the two parameters, and what the return shape implies for follow-up. The purpose is front-loaded with no redundant restatement of the name.

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 two-parameter read-only lookup with no output schema and no annotations, the description covers the source data, the call sequence, the return reference format, and the follow-up behavior. An agent has everything needed to call it correctly and interpret what it gets back.

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 both parameters are already documented including the "used when name is not given" precedence rule. The description's sequencing adds a little workflow context but no new semantics about the parameters themselves; baseline 3 is appropriate.

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 states a specific verb and resource ("looks up a schema in the Vapi API reference") and identifies the source of truth (the OpenAPI spec the SDKs are generated from). The final sentence about finding fields other tools accept through additionalFields makes its role distinct from the sibling documentation and CRUD tools.

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?

It gives a clear two-step workflow (use `search` to discover names, then `name` to fetch one) and a concrete use case, following referenced schemas when needed. It does not explicitly say when to prefer the sibling ask_vapi_docs instead, so the routing guidance is clear on this tool but not on its alternatives.

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