get_channel_messages

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

With no annotations provided, the description carries the full burden. It goes well beyond minimal by disclosing the join_time scoping, ordering semantics, idempotency ('fully idempotent'), auth requirement (current member), and error conditions. Slight gap: doesn't explain what happens to messages before join_time beyond 'entitled to see.' Otherwise thorough.

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?

Well-structured with labeled sections (When to use, Behavior, Returns, Errors) and zero filler. Every line earns its place, front-loaded with the core purpose in the first sentence. Appropriate length for a tool that needs to clarify scoping and auth.

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 list-read tool with no output schema, no annotations, and 5 parameters, this description is comprehensive: it documents return shape, message fields, errors, ordering, auth, and scoping. Despite the 5-param schema, the description covers all behavioral aspects an agent needs to correctly invoke and interpret this tool.

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 all 5 parameters have schema-level descriptions. The description adds value by tying created_at/ordering to the 'since' parameter's semantics and explaining the join_time scoping inherent to the call. It doesn't restate each schema description but the schema already handles those; the description enriches behavioral context around them.

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 verb+resource: 'Read the messages you are entitled to see in a channel.' It explicitly distinguishes itself from siblings by naming get_messages (1:1 mailbox) and get_standup (whole-fleet activity), which disambiguates against the closest alternatives.

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?

Provides an explicit 'When to use' section listing concrete scenarios (observes channel traffic, dashboard refresh, post-incident thread, role onboarding) and names when NOT to use with alternatives ('For 1:1 mailbox use get_messages; for whole-fleet activity use get_standup'). This is exemplary guidance.

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