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

Annotations already declare readOnly/openWorld/non-destructive, and the description adds real context beyond them: the auth requirement for private vs Community Spaces and the pagination continuation rule. It does not discuss rate limits or what happens with an invalid space_id, but the safety profile is well covered.

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 short sentences, front-loaded with the purpose and ordering, then pagination and access rules. No filler and nothing repeated from 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?

An output schema exists so return values need not be explained, and the description still usefully points at channels[].channel_id and has_more. Auth and paging are covered; only limit/regex behavior is left implicit, which the schema handles.

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 75%, so the baseline is 3; the description adds meaning by tying space_id to access rules ('a private Space needs membership') and by explaining the cursor loop via has_more. It says nothing about limit or the regex filter, leaving those entirely to 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?

States a specific verb and resource ('List the channels in a Space') plus a useful ordering guarantee ('General first'). The resource name distinguishes it from siblings like space_list_threads or space_list_members, though it never explicitly contrasts with them.

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 concrete operational guidance: paginate while has_more is true, and the access conditions ('No account is needed for Community Spaces; a private Space needs membership'). It stops short of naming an alternative tool for the cases where this one is wrong.

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