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

Annotations already declare readOnlyHint, idempotentHint, and openWorldHint, so the safety profile is covered. The description adds meaningful context beyond that: content-addressed permanence that keeps resolving after a repository is renamed, moved or deleted, and the source (Software Heritage archive). It stops short of stating rate limits or expected failure modes.

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, front-loaded with the fetch action and the id, with zero filler. The final 'Sourced from the Software Heritage archive' is slightly redundant with the earlier content-addressed sentence but adds source attribution.

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?

With one required parameter, full schema coverage, and no output schema, the description is appropriately complete: what is fetched, what fields are returned, accepted id formats, and the durability guarantee are all stated. It does not cover error behavior for unknown ids, but nothing major is missing for correct invocation.

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 100% and the schema already documents the id format, so baseline 3 applies. The description nonetheless reinforces that both a bare 40-hex id and a full swh:1:rev:<hex> SWHID are accepted, which matches and slightly enriches the schema's format guidance.

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?

Specific verb (Fetch) plus resource (one archived commit by Software Heritage revision id). The parenthetical clarifying the 40-hex id is the git commit sha removes ambiguity against a generic 'revision' tool, and it clearly stands apart from siblings such as origin_search or resolve_entity.

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 explains what the tool does and the accepting formats, and implies use when you have a SWH revision id or SWHID. However, it never says when NOT to use it or which sibling to prefer for related lookups (e.g., searching by content or resolving entities), leaving selection largely to inference.

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