Lifetime hours per skill (the ledger)

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It implies a read-only query via language like "ledger" and "Use to answer," effectively indicating no side effects. It also reveals output structure: sorted hours and next milestone. This is solid but not exhaustively explicit about auth or data freshness.

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 two sentences with no fluff. It front-loads the core concept (10,000-hour ledger), then specifies the content and provides an example query. Every sentence 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?

Given that there are no parameters, no output schema, and no annotations, the description must stand alone. It sufficiently explains what the tool returns (lifetime hours per skill, sorted, with the next milestone) and when to use it (answering a question about hours). No necessary information is missing for an agent to invoke it correctly.

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 tool has zero parameters, so the schema is trivially 100% covered. The description doesn't need to explain any parameters. Per the rule, 0 params yields a baseline of 4. The description's mention of "every #skill the user has tagged" clarifies the implicit scope of the query without needing parameters.

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 identifies the tool's resource (skills) and metric (lifetime focus hours). It specifies the exact purpose: to provide a ledger of hours per tagged skill, sorted by hours, with the next milestone. This is distinct from sibling tools like dwt_status or dwt_stats, which focus on different aspects.

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 description explicitly states a use case: "Use to answer 'how many hours have I put into X'." This gives clear practical guidance on when to invoke this tool. However, it does not mention alternatives or exclusions, so it doesn't fully meet the 5-level bar.

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