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

Annotations already declare readOnlyHint=false, idempotentHint=false and destructiveHint=false, so the mutation profile is covered. The description adds real value beyond that: the auth requirement ('Admin keys only') and the delivery fan-out (in-app, web, plus optional Slack channel post), which tells the agent the blast radius of calling this.

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, front-loaded with the effect and audience, then requirements, then delivery channels. Every sentence contributes and nothing is padded.

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 no-output-schema broadcast tool with annotations covering safety, the description covers auth and delivery sufficiently to call it correctly. The only notable gap is parameter constraints, which is captured in the parameter score rather than here.

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 0%, so the description carries the full burden, yet it only restates that title and body are required. It omits the schema's meaningful constraints (4000-char body, 120-char title), so an agent gets no format or length guidance it couldn't already infer from required fields.

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 ('Send'), resource ('announcement'), and audience scope ('every active member of the organization'), which cleanly separates it from the sibling announcements_query. An agent can tell instantly this is the broadcast/write path rather than a read.

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?

It gives prerequisites ('Requires title and body', 'Admin keys only'), which is useful gating context, but never states when to choose this over the sibling announcements_query or any when-not condition. Usage is implied by the broadcast framing rather than spelled out.

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