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

readOnlyHint=true already establishes the safety profile, so the bar is lower. The description adds that channels come back 'with recent state' and cites the POST endpoint, but says nothing about ordering behavior beyond the schema defaults, pagination semantics, or result size constraints.

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?

Two tight sentences with the core purpose front-loaded and examples adjacent. The trailing endpoint string adds little for an agent, but nothing is verbose or buried.

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?

A read tool with a rich 5-property schema and no output schema; the description sketches return content ('channels with recent state'). It is adequate, but it omits result shape, ordering guarantees, and how message_limit interacts with the payload.

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 all five parameters are already documented with defaults and bounds. The description's filter examples largely duplicate the filter property's own description, adding no meaning 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?

Clear specific verb+resource: 'List/filter channels by a Stream query filter', with concrete filter examples. It implicitly contrasts with the singular stream_get_channel, but never names or distinguishes itself from siblings such as stream_query_members or stream_get_channel explicitly.

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?

The filter examples illustrate usage context, and 'Default {} (all channels the app can see)' is in the schema. However there is no explicit when-to-use versus stream_get_channel (single channel) or guidance on pagination/limits trade-offs.

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