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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), and nothing in the description contradicts them. The description adds real behavioral context the annotations cannot: missing facts surface as [square-bracket] gaps, and the response bundles a letter plus last day plus a self-check checklist. It stops short of 5 only because it doesn't say what the checklist does with failures or how tone/notice conflicts resolve.

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?

Three sentences, front-loaded with the trigger, then the action, then the return shape and gap behavior. No repetition of the title, no filler, and every sentence carries distinct information.

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?

With 12 all-optional parameters and no output schema, the description correctly compensates by naming the three return artifacts (letter, last day, checklist) and how missing inputs are rendered. What remains thin is the interaction between notice and notice_days and the checklist's pass/fail semantics, though the schema largely covers the former.

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% across 12 parameters, so the schema already carries the per-parameter semantics (defaults, enums, date format, working-days toggle). The description adds only the high-level hint that the last working day is derived from the notice period; that is marginal value over the schema, matching the baseline 3.

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 (draft) plus specific resource (a short, professional resignation letter) and a second concrete deliverable (the last working day computed from the notice period). The opening trigger condition, 'when the user wants to resign,' cleanly separates it from the other drafting siblings (draft_cover_letter, write_summary).

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?

The first sentence gives an explicit when-to-use trigger tied to user intent. However, it names no alternatives and gives no when-not conditions (e.g., distinguishing itself from a general letter tool or when a user just wants notice math), so it stops short of the 5 bar.

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