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

Annotations already declare idempotentHint and non-destructive, but the description adds substantial context beyond them: re-attaching 'reports it and changes nothing', Slack requires a Slack app/browser and does not attach, apps cannot take organization channels, and a Valet account connection is required.

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?

Front-loaded with the core action and effect, and nearly every sentence carries operational information. The Slack sentence is slightly convoluted ('gives the step to take and attaches nothing'), but it earns its place as an exception case.

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 mutation tool with no output schema, the description covers prerequisites (Valet account connection), idempotency, special-case behavior (Slack, apps), and the sibling lookup tool. An agent has what it needs to call it correctly.

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% and already documents all three parameters, including that channel comes from list_channels and org_name defaults to the first-joined organization. The description adds little parameter-specific detail beyond the schema, so baseline 3 applies.

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 ('Attach an existing organization channel to an agent') plus the effect ('so the channel's events wake it'). It is clearly distinct from siblings like create_channel, detach_channel, and list_channels, which it references.

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?

Explicitly routes the agent: use list_channels to find the channel, use create_channel for apps (which take no organization channels), and recognizes that Slack is a special case where nothing is attached. It gives concrete when-to-use and when-not-to-use guidance.

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