messages_list

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

No annotations provided; description mentions it is an 'undocumented session endpoint,' which warns about stability. It explains compacted vs. uncompacted responses and batch capability but does not disclose permissions or side effects.

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?

Four concise sentences, front-loaded with main purpose. No wasted words; each sentence adds meaningful information.

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?

Given the presence of an output schema, description fully covers behavior: batch fetch, thread resolution, compact vs. full response, and the undocumented nature. Complete for a fetch tool.

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%, so baseline is 3. Description adds minimal value beyond schema; it restates the structure of message_ids and the effect of detailed, which is already in the schema.

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?

Description clearly states 'Batch-fetch full message objects by channel and timestamp' and distinguishes from conversations.history, which is a sibling tool. It specifies both purpose and scope.

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?

Provides a clear use case: hydrating saved/bookmarked items more efficiently than one conversations.history call each. Does not explicitly list when not to use, but context is sufficient.

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