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

Annotations already declare a safe, read-only, idempotent, closed-world operation, so the description only needs to add context. It does: it names the three legal regimes covered, says the output includes the governing rule and the extension position, and adds a non-legal-advice disclaimer. It does not describe output format or how the deadline is expressed.

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, no filler, with the core action and scope front-loaded and the disclaimer last. Every clause 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?

For a stateless calculation tool with no output schema, the description tells the agent what will be returned (deadline, applicable rule, extension position) and under which regimes. It is nearly complete; only the result's format/date representation is left implicit.

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 description coverage is 100%, so all three parameters are already documented, including the subtle UK clock-start rule. The description adds only marginal meaning by tying 'extension position' to the extended flag and enumerating the jurisdictions already present in the enum. 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 and resource ('Calculate the statutory deadline for answering a data subject access request') plus the jurisdictional scope and what the result includes ('the rule that applies and the extension position'). It is clearly distinct from siblings like breach_clock or dsar_letter_template, but never explicitly contrasts itself with a named alternative.

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 implied by the jurisdiction enum and the DSAR framing, and the 'General information, not legal advice' caveat sets a boundary. However, there is no explicit when-to-use guidance or routing against siblings such as breach_clock or dsar_request_scoping.

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