get_lexicon

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

Annotations are absent, so the description must disclose behavioral traits. It does so by stating the return content: 'Returns the full lexicon schema including type definitions, properties, descriptions, and cross-references.' This conveys what the agent can expect. It does not cover error handling or authentication, but for a simple read operation the transparency is adequate.

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 concise and well-structured: a one-sentence purpose, a sentence describing the return value, a usage statement, and a parameter definition. Every sentence provides unique value with no redundancy or filler. The front-loaded verb and resource make it easy to scan.

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 tool with only one parameter, no annotations, and an existing output schema, the description covers all necessary aspects: what it does, when to use it, what it returns, and what the parameter means. It is complete enough for an agent to select and invoke the tool correctly without further clarification.

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 coverage is 0% since the input schema only lists 'nsid' with no description. The description compensates fully with an Args section that defines 'nsid' as 'The Namespaced Identifier' and provides three concrete examples ('app.bsky.feed.post', 'com.atproto.repo.createRecord', 'chat.bsky.convo.sendMessage'). This gives the agent exactly what it needs to understand 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?

The description opens with a clear verb and resource: 'Retrieve a specific AT Protocol lexicon by its NSID.' This directly specifies what the tool does and distinguishes it from sibling tools like list_lexicons and search_lexicons by emphasizing lookup of a specific NSID rather than listing or searching. The additional clause 'complete definition of a specific endpoint or record type' reinforces the unique purpose.

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 provides explicit guidance with 'Use this when you need the complete definition of a specific endpoint or record type.' This tells the agent when to choose this tool. However, it does not explicitly mention sibling alternatives or state when not to use it, which would have made the guidance even stronger.

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