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

Annotations already declare it is a non-read-only, non-destructive, non-idempotent write. The description adds the real behavioral consequence that annotations cannot convey: the cost autopilot will not execute a held decision until it is released. It does not cover repeat-call behavior (relevant given idempotentHint=false) or what happens if the decision already ran.

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?

A single front-loaded sentence states the action first, then the consequence. The parenthetical CLI-twin reference is mildly extraneous for an agent but small enough not to hurt readability.

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 two-parameter mutation with full schema coverage and annotations, the description supplies purpose, precondition, and downstream effect. Remaining gaps (error behavior, whether release_cost_decision is mandatory to resume, return value) are minor since no output schema exists but the action is simple.

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 coverage is 100%, so both parameters are already documented, including the decision_id reference to list_cost_decisions. The description only reinforces that the note is 'your reason', adding marginal meaning over the schema. Baseline 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 (hold) and resource (an approved cost decision), plus a scope qualifier ('before it ran') that separates it from execute_cost_decision or approve_cost_decision. It does not name those siblings explicitly, so an agent must infer the boundary rather than read it.

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 phrase 'an approved cost decision before it ran' gives a clear precondition for use, and 'until someone releases it' implicitly points to release_cost_decision as the counterpart action. There is no explicit when-not-to-use statement or named alternative tool.

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