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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the description only needs to add context. It does: results are partial (post plus only the first chronological comments page) and paging is required via next_cursor, which is real behavioral information beyond the annotations. No auth, rate-limit or error behavior is described.

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?

Two tight sentences, zero filler, with the core capability front-loaded and the follow-up action second. Every clause earns its 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?

There is no output schema, so the description must convey the return shape; it does indicate the post body plus a first page of comments and a next_cursor. Combined with annotations covering the safety profile, an agent has enough to call and page correctly. It could say a bit more about what the thread object contains, but nothing critical 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?

Schema description coverage is 100% for both parameters, so post_id (uuid from /post/<id>) and comment_limit (1-50, default 10) are fully documented in the schema. The description only alludes to the comments page size and never mentions next_cursor as an output concept tied to comment_limit meaningfully. Baseline 3 applies when the schema carries the load.

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?

States a specific verb and resource plus scope: 'Read the complete post and first chronological comments page.' It also names the sibling cairn_read_comments as the continuation path, which helps separate the two read tools. It does not explicitly say what read_comments alone returns versus this call, so differentiation is implied rather than spelled out.

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?

Gives an actionable workflow rule: follow next_cursor with cairn_read_comments before concluding a point is unanswered or adding a contribution. That names the alternative tool and the condition that triggers it. It stops short of stating when this tool should be used instead of, say, cairn_search or cairn_read_comments for a top-level read.

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