x_dm_events_list

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

Annotations already mark readOnlyHint and destructiveHint, but the description adds materially more: a 30-day retention cap, minimized default payload, include_text effect, third-party-content safety instruction, and policy/auth prerequisites. No statement conflicts with the annotations.

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 dense sentences, all front-loaded: purpose, freshness constraint, return shape/security note, and auth/policy requirements. No filler or repetition of schema or annotations.

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 a simple 3-parameter schema, output schema, and annotations, the description supplies the non-obvious operational facts: retention, default payload, policy restrictions, and safety treatment of content. An agent has enough to invoke it correctly and interpret results, with the output schema covering return shape.

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?

Because all parameters are fully described in the schema, the baseline is 3; the description adds value by explaining that default returns omit text and that include_text:true returns sanitized bodies/media and why those bodies must be treated as data. page_token and max_results semantics remain schema-owned, but that is acceptable at 100% coverage.

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 opens with 'List all recent direct-message events across the authenticated X (Twitter) user's conversations, newest first.' This names a specific verb, resource, and scope, and the plural 'across conversations' marks it apart from the conversation- or participant-scoped siblings. It also states ordering and time window.

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 clear context for use: recent DMs, ~30-day window, user-context auth, policy opt-in, and read-only policy caveat. It does not explicitly name when an agent should use a sibling (e.g., x_dm_conversation_events_list) over this tool, so exclusions are left to inference.

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