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

Annotations already declare readOnly/idempotent/non-destructive, yet the description adds real substance: the provenance block per field, last_close contents, confidence reporting, and the resolved_from marker. The only weakness is an internally inconsistent cost message — 'free, no API key required' up front versus '1 credit (EUR 0.01) per call on an agent key' at the end.

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?

Front-loading with 'THEN:' is effective, but the cost model is stated twice in different terms, and the provenance/last_close sentence is a dense run-on. The content is useful; the packaging wastes space and creates ambiguity.

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 no output schema, the description carries the return-shape burden and does it: provenance, last_close, resolved_from, and the confidence notion are all named. Cost, resolution quirks, and slug provenance are covered, so an agent has everything needed to call 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?

Schema coverage is 100%, so baseline would be 3, but the description adds meaning beyond the schema by explaining why the slug cannot be derived from the display name and what happens when a near-miss occurs. That is behavioral guidance the schema types alone do not convey.

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 ('get the detailed profile of one fund') and pins the input to a slug returned by a named sibling. An agent can distinguish this from search_funds or get_fund_signals 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?

Explicitly sequences the workflow ('THEN... using a slug returned by search_funds'), states a negative rule ('Do not guess the slug... it will usually be wrong and the call is wasted'), and documents edge-case routing (near-miss resolves only on exactly one match; ambiguous names are listed, not guessed).

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