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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is covered. The description adds value annotations cannot: 'The result carries the inner tool's freshness and cite', telling the agent the proxy forwards metadata from the inner tool. It stops short of disclosing error propagation or argument-validation behavior.

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 essential routing rule is front-loaded in the first clause, which is good. But the body is a single enormous paragraph enumerating dozens of tools and their fields, largely duplicating what the sibling `catalogue` tool exists to provide — useful at selection time, yet far from tight.

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 proxy/dispatcher with a nested arguments object and no output schema, the definition covers what an agent needs: which names are valid, which tools bypass it, where schemas live, and that freshness/citation metadata rides along. It lacks only failure-mode behavior for inner-tool errors.

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 'tool' and 'arguments' are already documented — that alone would be a baseline 3. The description earns the extra point by enumerating concrete valid tool names and their key arguments (e.g., support_status {product, version}, calendar_facts {country, kind, year?, region?}), which is exactly the information the bare schema lacks.

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 — 'Run any Data Butler tool by name' — and explicitly scopes itself to 'the long tail not listed here', naming uk_rates_lookup, domain_provenance, package_provenance and take_home_pay as tools that are listed directly. That differentiation lets an agent decide between this dispatcher and its siblings without opening a 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?

It implies the when-to-use rule clearly: reach for `call` only for tools not exposed directly, and it points to `catalogue` for schemas. What's missing is explicit guidance on when a listed sibling like get_fact or resolve_fact should be preferred over routing the same intent through `call`.

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