Chat messages

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

Annotations already state readOnlyHint=true, idempotentHint=true, destructiveHint=false. The description reinforces 'Read-only' and adds that it does not mark chat as read, which is beyond annotations. No contradictions.

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 sentences, no wasted words. Front-loaded with main function. Each sentence adds value: purpose, read-only note, required parameter, pagination, voice file redirect. Excellent efficiency.

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?

No output schema, but description adequately specifies return content (text, images, voice, links, date, author). Provides context for parameters and links to related tools. Annotations cover safety. Complete for agent to understand and use tool correctly.

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 covers all 4 parameters with descriptions (100% coverage). Description adds context: chat_id source, pagination roles for limit/offset, default for user_id. This enriches understanding beyond 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?

The description clearly states it returns messages of a specific chat, sorted newest to oldest, and lists the types of content included (text, images, voice, links, date, author). It distinguishes itself from siblings like messenger_chat_read and messenger_get_chats_v2 by specifying its unique purpose.

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?

Explicitly says it is read-only and does not mark the chat as read, directing to messenger_chat_read for that. Requires chat_id from messenger_get_chats_v2. Provides pagination guidance with limit/offset. Also notes use messenger_get_voice_files for voice file URLs. This covers when to use and alternatives.

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