channel_messages

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

With no annotations, the description carries the behavioral burden. It does disclose useful behavior: the results are the latest messages, ordered oldest first, for either a channel or thread. It does not mention pagination semantics, output shape, or access requirements, leaving some transparency gaps.

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?

The description is a single, economical sentence with the key information front-loaded: resource scope, recency, and ordering. It is easy to parse and contains no filler, though it could carry slightly more detail without losing conciseness.

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?

For a flat four-parameter list tool, the description plus schema is minimally sufficient to make a call: channel_id is requiredainer and limit/before/after are explained. Since there is no output schema, the return shape is left implicit, and no auth, rate limits, or pagination behavior are mentioned. This is adequate but not complete.

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 description coverage is 100%, so the schema already documents all four parameters. The description adds helpful framing around 'latest' and 'oldest first', which clarifies the meaning of before/after/limit, but it does not add significant parameter-level detail beyond 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?

The description identifies a concrete resource ('channel or thread') and a clear result ('latest messages'), and even adds ordering ('oldest first'). It is distinct from siblings like dm_messages or channel_search, though it lacks an explicit verb like 'list' or 'fetch', so it is not a 5.

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?

There is no explicit 'use this instead of X' guidance. However, 'latest messages in a channel or thread' implies this is the listing tool for recent messages, which differentiates it from channel_search and message_context. The usage context is inferable, but not spelled out.

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