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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false, and openWorldHint, so the safety profile is fully covered by structured data. The description adds one genuinely new behavioral fact — that the cross-board listing is ordered by recent activity rather than creation date — plus provenance via the service URL, but says nothing about result volume, pagination, or empty-board behavior.

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 short sentences, with the scope distinction front-loaded where an agent will read it first. The trailing service/URL line is minor provenance overhead rather than tool guidance, but it costs little.

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 only two optional parameters, full schema coverage, and rich annotations, the definition covers what an agent needs to call this correctly. The absence of an output schema means the return shape (topic fields, ordering of the whole-board case) is only partially conveyed, which keeps it short of a 5.

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%: forum (slug from list_forums, omit for whole board) and limit (1-100, default 30) are both fully documented in the schema. The description only restates the forum-omission case, adding no format or edge-case detail beyond what the schema already says, so the baseline of 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?

The description names the resource (topics) and its two scopes: a single forum, or the whole board when no forum is supplied. That is clear enough to separate it from read_topic, read_post, and list_forums, though it never uses an explicit verb like 'list' or 'browse' and leans on the title for that framing.

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 'no forum = whole board' clause is really a parameter behavior rather than a tool-selection rule. There is no statement of when to prefer search_posts or read_topic over this listing tool, and no mention of the ordering implications for agents that need chronological rather than recency-ordered results.

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