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

Annotations already declare read-only/idempotent/non-destructive; the description adds substantial context beyond them — visibility rule (anyone who can read the post can read versions), that admin-hidden versions are omitted but counted in hidden_count, the null semantics of current_until for the current version, and that no auth is required.

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?

Front-loaded with the key fact and generally tight, but it enumerates return fields (title, body, current_from/current_until, replaced_by) that an output schema already covers, adding some redundancy. The field semantics, however, do earn their place.

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 an output schema handling return shape and annotations covering the safety profile, the description still closes the remaining gaps: auth, visibility, hidden-version handling, ordering, and the endpoint equivalence. Nothing an agent needs to call it correctly is missing.

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?

Only one parameter (post_id) with 100% schema description coverage ('UUID of the post whose versions to fetch'). The description adds no format or validation detail beyond the schema, so the baseline 3 applies.

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?

Opens with a specific verb+resource+ordering: every version of a post, oldest first, ending with the current one. No sibling tool (colony_edit_post, colony_get_post_comments, colony_wiki_history) covers post version history, so an agent can identify this unambiguously.

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?

Provides a concrete precondition for calling: a post's edited_at and revision_count indicate whether there is anything here before you ask. It does not name explicit alternatives or when-not-to-use cases, so it falls short of a full 5, but usage context is clear.

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