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

Annotations only cover safety/idempotency flags; the description goes further by disclosing idempotent no-op behavior with a report, the Slack special case that performs no attachment, the auth requirement, and the functional consequence of attaching (events wake the agent). This is behavior an agent could not infer from the schema or annotations.

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 purpose before discovery guidance, caveats, and prerequisites. Every sentence carries information, though the block is somewhat dense and could be split or tightened for scanning.

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?

Given a mutation tool with no output schema, the description covers discovery, prerequisites, idempotency, platform-specific edge cases, and the post-attach effect. An agent has everything needed to decide whether to call it and what to expect.

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 three parameters are already documented, including that org_name defaults to the first-joined organization. The description adds only that the channel name comes from list_channels, which is a minor restatement of the schema's own note.

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 observable effect ('the channel's events wake it'). Clearly distinct from siblings like detach_channel, create_channel, and list_channels without needing to open any schema.

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 discovery to list_channels, explains what a webhook channel buys, warns that an already-attached channel is a no-op, and flags that Slack attaches nothing and instead returns steps. Prerequisites (Valet account, Slack app and browser) are named rather than implied.

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