Countdown

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

The description does not mention any side effects, state changes, or world modifications. While the annotations (readOnlyHint: false) indicate that the tool mutates state, the description itself adds no behavioral context beyond the generic verb 'manage'.

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?

The description is concise, using two clear sentences with direct guidance. The 'Use when' and 'Do NOT use when' structure makes it easy to scan and apply, with no redundant 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?

Given the simple nature of the tool and the complete schema coverage, the description provides sufficient context for correct usage. It covers the primary action list, the exclusion case, and a pointer to the sibling tool, making it self-contained.

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?

The schema provides descriptions for all parameters (100% coverage), so the baseline is met. The tool description does not add extra meaning to the parameters; it only lists actions that map to the enum values. No further clarification is needed beyond the schema.

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?

The description clearly states the tool manages countdown timers and lists the specific actions: starting, advancing, removing, or listing clocks. It also distinguishes from vow tracking by pointing to the vow tool, making the purpose unambiguous.

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?

Explicit usage guidance is provided: 'Use when: starting, advancing, removing, or listing clocks' and 'Do NOT use when: tracking a vow's progress — use vow (action: milestone)'. This gives clear direction and a named alternative.

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