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

Annotations only supply destructiveHint=true and a title, so the description carries real weight: it flags the mutation, clarifies that a draft is staged rather than sent, states that an SSO URL is returned for completion in the UI, and cites the endpoint. It also softens the misleading destructiveHint by clarifying no message is sent.

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?

A single dense paragraph with the mutation warning front-loaded, followed by mechanism, alternative, endpoint, and return shape in descending priority. No sentence is filler.

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 nested inputs and no output schema, the description covers the write semantics, the human-in-the-loop workflow, the endpoint, and the return value (SingleSignOnUrl). Nothing an agent needs in order to call it correctly is missing.

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%, so both the contacts array and the escape-hatch 'fields' object are already documented in the schema with PascalCase examples. The description only restates 'with the given contacts' and adds no syntax beyond what the schema provides, so the 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 ('stages a broadcast' / 'creates a DRAFT') and immediately bounds the scope ('does NOT send anything'). It explicitly contrasts with the sibling create_broadcast, so an agent can distinguish the two without opening a 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?

Gives an explicit selection rule: 'Safer than create_broadcast when a human should review before sending.' This names the alternative and the condition that should route the agent to it, leaving nothing to inference.

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