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

Annotations only carry destructiveHint=true; the description adds critical behavioral context that annotations cannot: 'This emails real people' signals an external side effect, and the version/endpoint detail grounds the call. It doesn't cover reversibility or failure modes, but adds real value beyond annotations.

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: purpose front-loaded, then the impactful side-effect warning. Zero waste; endpoint reference is compact.

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 3-param mutation with no output schema, the description covers purpose, side-effect, and endpoint. Missing prerequisites (must be a draft, recipients already added) and whether the operation is reversible keep it from a 5.

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%; all three parameters are documented in the schema (documentId, message, subject). The description doesn't add syntax or formatting guidance beyond what the schema provides, so 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?

Specific verb+resource+scope: 'Send a draft document to its recipients for signature.' Distinguishes from sibling redistribute_document by the 'draft' qualifier, and from add_recipient by naming the send action.

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?

Implies usage – send a draft (prerequisite implied), and the sibling list shows redistribute_document as the re-send alternative, but the description doesn't explicitly say 'use this only for drafts, not already-sent documents.' Clear context without explicit exclusions.

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