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

Annotations already declare not-read-only, not-destructive, not-idempotent; the description adds genuine behavioral context by explaining the outcome — the card returns to review where it can be changed and re-approved — and how the invalid-state case is handled. It doesn't discuss permissions or error text, but it goes beyond the annotations without contradicting them.

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, front-loaded with the core action before the edge case. The em-dash and colon construction is dense but every clause (the two waiting states, the already-left case) 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?

No output schema exists, so the description carries return semantics — it explains that the card goes back to review and that an already-left letter is reported as such. That covers the key outcome an agent needs for a single-parameter state-change tool.

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?

With one parameter and 100% schema coverage, the schema already documents card_id and points to list_open_cards as its source. The description adds no further syntax or format meaning, so the baseline of 3 applies.

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 (take back an approved letter not yet sent) and sharpens the scope with two qualifying states: waiting for the lead's hours or the sweep. An agent can distinguish it from state changes like reject_a_card or stop_a_card by the condition attached, though no sibling is named explicitly.

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?

Gives a clear when ('has not left yet' — waiting on lead hours or sweep) and a when-not ('a letter that has already left is answered as such'), so the agent knows the boundary. It stops short of naming an alternative tool for the already-sent case.

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