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

Annotations already declare readOnlyHint=false, destructiveHint=false, and openWorldHint=true, so the safety profile is partly covered. The description adds genuinely useful context beyond that: it changes guidance for agents and people, sends no message, and does not change channel access — exactly the kind of effect scope an agent needs before mutating. It does not address how to reconcile idempotentHint=false with the idempotency_key parameter.

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 short sentences with no filler, front-loading the core action, then the clearing rule, then the effect scope. Every sentence carries distinct information.

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 7-parameter mutation tool with no output schema, the description covers what changes, what does not change, and how to clear a field, which is enough for an agent to invoke it correctly. The remaining gap is the rationale behind the required reason parameter, which the description names but never explains.

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 86%, so the schema carries most parameter documentation and the baseline would be 3. The description earns above baseline by explaining that 'Null clears a field,' which clarifies the semantics of the nullable vendor and purpose anyOf types that the schema shows but does not explain.

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?

The description states a specific verb and resource: set the vendor and purpose metadata for a selected Slack channel. It clearly distinguishes itself from sibling summer_slack_channels_list in spirit (metadata write vs. listing), though it never names a sibling explicitly. The 'describe' in the tool name risks reading as a read operation, and the description does correct that by saying 'Set'.

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?

Usage is implied: use it to annotate a channel's vendor/purpose, and 'Null clears a field' tells the agent how to remove metadata. However, there is no explicit when-to-use/when-not guidance, and 'with a reason' does not explain why the reason is required or what an acceptable reason looks like beyond the schema's length bounds.

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