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

The annotations already establish readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds useful access/cost context ('Free; no key needed'), but it does not describe the return shape or what happens when req_id is invalid or unknown.

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 sentences with no filler, and the free/no-key information is useful. It could be more front-loaded around the actual retrieval action, so it falls short of a 5.

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 simple one-parameter read tool, the schema and annotations cover most of what an agent needs. However, without an output schema, the description should do more to explain what the returned requirement contains and how failures are surfaced.

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 single required parameter, req_id, is fully documented in the schema, including the 'req_...' ID format. The description adds no parameter meaning beyond that, so the high schema coverage makes 3 the appropriate 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 names the domain concept (viewing what a buyer requires of suppliers) but does not clearly state the operation as retrieving a specific requirement by ID. It also does not distinguish this from siblings such as supplier_requirement_create or supplier_proof_inbox, so the title and tool name carry much of the clarity.

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?

There is no guidance on when to use this tool versus alternatives like supplier_requirement_create, supplier_proof_inbox, or supplier_certs. The only usage-adjacent information is 'Free; no key needed', which is access context rather than selection guidance.

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