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

With no annotations, the description carries the full burden of behavioral disclosure. It does this well by detailing what the proof chain contains, including source URI, retrieval time, hashes, event chain, corpus commit, index build, and stamp signature. This tells the agent what to expect in the response, though it does not explicitly state side-effect-freedom or failure behavior.

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 a single, compact sentence that front-loads the core purpose ('Proof chain for one lex_id') and then efficiently lists the output components in a colon-separated sequence. Every element adds useful information, with no filler or redundancy.

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?

Given the tool's moderate complexity (2 params, no output schema, no annotations), the description provides a solid inventory of return values, which is sufficient for a straightforward lookup tool. It lacks usage guidance and deeper behavioral notes, but the enumerated components largely compensate for the absence of an output schema. Sibling tool names also help contextualize its role.

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 input schema already provides descriptions for both parameters (lex_id as 'full lex_id' and language as 'optional'), achieving 100% coverage. The description adds minimal parameter-level meaning beyond confirming the lookup is for a single lex_id; it does not explain how 'language' affects the proof chain or whether it is required for certain lex_id formats.

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 identifies the tool's output as a 'proof chain' for a single lex_id and enumerates the specific components (source URI, hashes, event chain, etc.). This distinguishes it from siblings like 'article_history' or 'timeline' by focusing on verifiable provenance rather than general history. However, it lacks a strong action verb (e.g., 'retrieves' or 'generates'), so it reads more as an output description than an operation.

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 'for one lex_id' implies the tool is intended for per-identifier provenance lookup, which provides some usage context. But there is no explicit guidance on when to prefer this over siblings like 'coverage' or 'article_history', nor any mention of exclusions or alternative tools.

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