Chat messages

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

Description declares read-only behavior and that it does not mark chat as read, adding value beyond annotations which already indicate readOnlyHint. Also specifies sorting order and content types.

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?

Three sentences, each with distinct value: main purpose, read-only clarification, and related tool. Front-loaded with key functionality, no waste.

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 high schema coverage, annotations, and no output schema, the description covers purpose, inputs, pagination, and related tools well. Could mention return format briefly, but still adequate for agent invocation.

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 description adds minimal new information beyond schema. It reiterates chat_id source and pagination purpose, but does not compensate for lack of enums or nested objects. Baseline 3 is appropriate.

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 specifies the tool returns messages (text, images, voice, links, date, author) sorted newest to oldest. It clearly states the resource (messages of a specific chat) and verb (returns), and distinguishes from siblings like messenger_chat_read and messenger_get_voice_files.

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 states requirements (chat_id from messenger_get_chats_v2), pagination via limit/offset, and when not to use (read-only, use messenger_chat_read to mark read). Provides alternatives for voice file downloads.

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