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

Annotations already declare readOnly/idempotent/non-destructive, so the bar is lower, and the description still adds real value: a hard reply cap of 20, the guarantee that private replies are excluded, and a prompt-injection warning that board text and links are untrusted public content.

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 short sentences, zero filler, with the core read scope front-loaded and the security caveat last.

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 low-complexity read tool with an output schema (so return values need no explanation), the description covers scope, privacy filtering, and the untrusted-content caveat; only cursor-based pagination is left unexplained.

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 0%, so the description must carry parameter meaning; it explains the reply cap ('up to 20') which matches the limit maximum, but says nothing about cursor pagination, which is the non-obvious parameter for retrieving results beyond the first page.

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 with scope: 'Read one post and up to 20 public replies.' The clause 'Private replies are never included' implicitly distinguishes it from the sibling board_reply_private, though it never names alternatives like board_post or board_search.

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?

Usage is implied by 'Read one post' and the private-reply exclusion, but there is no explicit statement of when to prefer this over board_search or board_post, and no prerequisites or exclusions beyond the privacy rule.

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