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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so the safety profile is covered. The description adds value by disclosing that the response includes the deadline's source and history, plus that the call is free — behavioral facts not present in the structured fields.

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?

One sentence, front-loaded with the operation and resource, with no filler. Every clause (source collection, id lookup, returned contents, cost) 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 single-record lookup with no output schema, mentioning that source and history are returned covers the main return-shape gap, and annotations handle safety. It stops short of noting behavior on an unknown id, which is a minor omission for this complexity.

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% and the single id parameter is fully documented with its pattern and origin, so the schema does the heavy lifting. The description repeats 'by its id' and 'from eu_compliance_deadlines' without adding format or lookup semantics 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?

States a specific verb (fetch one) and resource (EU compliance deadline) and pins it to the source collection 'eu_compliance_deadlines', which implicitly distinguishes it from the plural list sibling. An agent can tell it is a single-record lookup by id without opening the schema.

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 'by its id' phrasing implies the precondition that you must already have an id, and the reference to eu_compliance_deadlines hints at the list-then-detail flow. However, there is no explicit when-to-use/when-not guidance or named alternative for cases where the id is unknown.

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