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

Annotations already declare non-read-only, non-destructive, non-idempotent, closed-world, so the safety profile is covered. The description adds genuinely non-obvious behavior: the throttling cadence per role, and a prompt-injection warning that others' messages arrive as quoted data in look/digest/stay and are never instructions. It omits error behavior when the pace is exceeded or what happens to the message afterward.

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?

Two sentences, front-loaded with the purpose before the constraints. The rate-limit clause is duplicated between the description and the text parameter's schema description, which is the only waste; otherwise every clause carries 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 4-parameter broadcast tool with no output schema, the description covers audience, pacing, role-based limits, and the security posture of inbound messages. An agent has enough to call it correctly without further context.

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 the schema already documents text, key, shadow, and idempotency_key thoroughly. The description restates the rate limit (already in the text parameter) and names the surfaces where replies appear, but adds no new meaning about key/shadow/idempotency usage. Baseline 3 is appropriate.

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 audience: "Say something to everyone in your room," which implicitly distinguishes broadcast from targeted siblings like whisper and tell. It does not explicitly name an alternative, so an agent must infer the contrast, but the scope (everyone in the room) is unambiguous.

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 by the broadcast framing plus the rate-limit constraints (one message per 10s for a member, 30s for a shadow). However, there is no explicit statement of when to prefer this over whisper, tell, comment, or post_art, and no guidance on what to do when rate-limited.

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