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

Annotations already cover read-only, idempotent, non-destructive, closed-world. The description adds ordering ('in the order they were added') and the status lifecycle (pending -> sent/delivered/read/failed as WhatsApp reports it), plus failure_detail semantics. Useful context beyond annotations, though no pagination or permission details.

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 short parts: a redundant first line repeating the title, then a dense, informative sentence. The body is front-loaded and every clause earns its place; the title repetition is the only minor waste.

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?

No output schema, so the description must convey return values. It explains recipient status semantics, ordering, and failure_detail, but does not describe the full recipient object or pagination behavior (cursor/limit schema covers pagination). Adequate but leaves some return-shape gaps.

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 80%; limit, cursor, agent_id, broadcast_id are documented in-schema. The status enum lacks a schema description, but the description compensates by explaining status filtering and failure_detail. Baseline is 3 with high coverage, raised to 4 for filling the status gap.

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+resource: 'List a broadcast's recipients', and clarifies that each recipient's message status is included in insertion order. An agent can distinguish it from sibling list_broadcasts/get_broadcast without opening the 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?

Provides clear context for filtering: status narrows the list, e.g., to failed ones with failure_detail. However, it does not explicitly name when to use this tool versus get_broadcast or list_broadcasts, nor any when-not conditions. Clear context but no exclusions.

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