bili_dm_sessions

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

With no annotations, the description carries the burden, and it does useful work by flagging 'Untrusted external data' (a prompt-injection warning) and disclosing the 'up to 30' ceiling. It does not state auth requirements, pagination behavior, or explicitly that the operation is read-only beyond the word 'Read'.

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, front-loaded sentences with no filler; the untrusted-data warning is placed where it will be read before invocation. Minor jargon ('stable talker UIDs') asks the reader to already know the domain.

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?

Return values need not be described since an output schema exists, and the security caveat is a real addition. However, for a listing tool with three closely related DM siblings, the absence of routing guidance leaves a meaningful 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?

The single 'limit' parameter has 0% schema description coverage, so the description must compensate. 'Up to 30' conveys the maximum cap for that parameter, which is genuinely useful, but it does not explain the default of 20 or how the limit is applied.

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?

Specific verb ('Read') plus resource ('private-chat sessions') and a hint of the fields returned ('talker UIDs and last messages'). It is distinguishable from bili_dm_unread and bili_dm_history by focusing on the session list rather than messages or counts, though the boundary is only implied.

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?

No statement of when to choose this over bili_dm_history, bili_dm_unread, or bili_dm_send. An agent must infer from the name alone that this lists conversation threads rather than reading one thread's messages.

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