Read a mention

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

Beyond readOnlyHint/openWorldHint, the description discloses the concrete payload shape and, more importantly, flags that author and text fields originate outside the workspace and should never be treated as instructions — non-obvious safety context that structured fields cannot convey. It is consistent with the openWorldHint annotation and adds real operational value.

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 zero filler: the read-only scope is front-loaded, the returned fields follow, and the injection caution closes. Nothing is repeated from the title or schema unnecessarily.

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 one-parameter read tool with no output schema, the description covers returned content and the key behavioral risk (untrusted external text). The only untouched item is what happens when the id is unknown or not visible to the caller, a minor gap.

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 coverage is 100% and the single id parameter already documents its pattern and that ids come from postfjord_list_mentions. The description adds no format, lookup, or error semantics on top of that, so the baseline 3 is 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?

The first sentence names a specific verb and resource ('Read only. One mention') and then enumerates exactly what comes back (link, author handle, text, rating, score), which cleanly separates it from postfjord_list_mentions. It stops short of explicitly naming the list tool as the sibling, but the singular scope is unambiguous.

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 only implied: a reader infers this is the follow-up to a listing call because it returns one record. No explicit when-to-use, when-not-to-use, or named alternative appears in the description (the pointer to postfjord_list_mentions lives only in the id parameter schema).

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