Darc Dok Valid On

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

Annotations already declare readOnly, idempotent, non-destructive, closed-world, so the safety profile is covered. The description adds genuine domain behavior beyond that: window-bounded validity for special DOKs and the replaced_by signal for merged codes, which is the kind of nuance an agent could not get from annotations alone.

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 tight sentences with no filler, front-loading the core question and then the two edge-case behaviors. Every clause carries information an agent needs.

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 an output schema present, return values need not be explained, and the description supplies enough domain context for a 2-parameter read tool. A brief pointer to how a false result differs from an unknown code would make it fully complete.

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 code and on_date are already documented with examples and the YYYY-MM-DD format, making the baseline 3. The description adds framing about special DOK codes but no new syntax or constraint detail 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 states a specific predicate (validity of a DOK/special DOK on a date) and clarifies two non-obvious domain rules: special DOKs are valid only within the published window, and merged codes expose replaced_by. An agent can tell this is a point-in-time validity check rather than a lookup or search, 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?

Usage is only implied by the phrasing 'whether ... was valid on a date'; there is no explicit when-to-use, when-not-to-use, or routing against darc_dok_lookup, darc_dok_codes_for, or darc_dok_search. The agent must infer that this is the tool for temporal validity questions versus general code retrieval.

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