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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, so safety is covered structurally. The description adds real context beyond that: 'Nothing here has been sent' pins down the state of the returned records, and 'with the full text of each one' discloses payload richness. It omits pagination/volume behavior, keeping it short of a 5.

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, zero filler, and the core scope plus the unsent-state constraint are front-loaded ahead of the routing guidance. Every clause earns its place.

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 single-parameter read-only list with no output schema, the description supplies what an agent needs: what is returned (full text), the record state (unsent), and the branch points to sibling actions. Nothing material 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?

One required parameter at 100% schema coverage, so the schema already documents workspaceId fully, including how to discover valid values via get_status. The description adds nothing about the parameter, which is the expected baseline when the schema does the work.

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+scope: drafts of outreach emails awaiting a decision, and explicitly says the full text of each is returned. It is distinguishable from siblings like list_sent, list_inbox, and get_draft_reply without opening any 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?

Names the exact alternatives and the condition for each: edit_draft to change one, discard_draft to drop one, approve_batch to send the rest. This routes the agent's next action precisely rather than leaving follow-up to inference.

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