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

Goes beyond the annotations (which only cover readOnly/idempotent/destructive) by disclosing PATCH-style partial-update semantics and the 409 failure mode on locked broadcasts. These are important operational traits an agent cannot infer from the structured fields alone.

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 tight sentences, front-loading the DRAFT constraint so the most important precondition is read first. Every clause earns its place with no 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 no output schema, the description covers the key behavioral facts (draft-only, lock behavior, 409) that the 100%-covered schema and annotations do not. It omits return-value/confirmation details, but no output schema exists to require them.

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 every parameter is already documented (including the detailed enum guidance and empty-string-clears semantics). The description only recaps a subset of the editable fields, adding no syntax or format detail beyond the schema; 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 (Edit) and resource (broadcast's fields) constrained to DRAFT broadcasts, and distinguishes itself from the many other update_* siblings by naming its scope. An agent can tell this apart from create_broadcast, schedule_broadcast, or update_sequence immediately.

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 gives the when ('fix the name, subject override, audience segment, template, or sender before sending') and the when-not (scheduled/sending/sent broadcasts are locked and return 409). It does not name the alternative tool for editing a non-draft, but the prerequisite condition is fully spelled out.

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