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

With annotations already declaring readOnly/idempotent/non-destructive, the description adds substantial extra context: thread order (oldest first), message kinds (customer/staff/system), attachment handling (file names only, opened in the web app), field meanings for `following` and `reopen_until`, company-wide visibility, and how AI-agent writes are labelled. This is behavior beyond what any annotation conveys.

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?

The lead sentence duplicates the title verbatim, and the attachment/web-app point is made twice ('Attachments show as file names only — people open them in the web app' and 'Text only: files are attached in the web app'), so not every sentence earns its place. The content is otherwise dense and reasonably front-loaded, but the redundancy costs it.

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 properly carries the return-shape burden: it explains the thread, the message kinds, how attachments appear, and the meaning of `following` and `reopen_until`. An agent has everything needed to call it and interpret the result.

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% and the single `case_id` parameter is fully documented in the schema (pattern, ULID, spec reference), so the schema does the heavy lifting. The description adds no additional meaning about the parameter itself (no format examples or ID-sourcing guidance), making the baseline 3 correct.

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 concrete verb and resource ('One case ... with its whole thread, followers and context') and immediately distinguishes support cases from issues, naming the sibling tools an agent might otherwise confuse it with. An agent can tell exactly what this retrieves without opening the schema.

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 explicit when ('user wants help from the BoardMark team or reports a problem with BoardMark itself — a bug, signing in, billing, a feature request') and an explicit when-not ('never for the user's own project work') with the alternative named (create_issue, search_issues). Nothing is left to inference.

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