List channels

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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description adds non-obvious behavior the annotations cannot convey: the default membership filter and, crucially, the meaning of the truncated:true field in results — useful since there is no output schema.

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 tight sentences with zero filler. Scope, the flag that changes it, and truncation handling are each front-loaded in order of importance.

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 read-only, open-world list tool with no output schema and no required params, the description covers scope, the opt-out flag, and truncation semantics. Pagination via cursor is only inferable from the schema, and no result shape is described beyond the truncated flag, leaving minor gaps.

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%, and the one undocumented parameter, joined_only, is exactly what the description explains, including its default and inverse use. limit is only alluded to ('raise the limit') and cursor is not discussed, but the key gap in the schema is compensated.

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 channels') and immediately clarifies scope: member channels by default, public channels only with joined_only=false. It is unambiguous, though it does not name or contrast against any sibling tool (e.g., search_messages), so differentiation is left implicit.

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 explicit conditions for the non-default behavior ('set joined_only=false to browse public channels') and tells the agent what to do when truncated is true ('narrow the query or raise the limit'). It does not address when to prefer a different listing/search tool, so it stops short of full alternative routing.

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