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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, and the description corroborates the closed-world hint with a concrete list of known catalogue gaps. Beyond that it discloses the result cap ('up to 25 matches') and the exact fields returned (slug, name, unit, frequency, source, years covered), which the annotations do not cover.

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 purpose is front-loaded in the first clause, and every later sentence carries distinct load (trigger, return fields, downstream slug usage, coverage gaps). The long catalogue enumeration in sentence one is defensible for a keyword-search tool but is the bulkiest part and could be compressed.

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?

Although there is no output schema, the description names the returned fields and the result cap, explains what to do with the slug downstream, and pre-empts the most likely failed searches with an explicit exclusion list. For a two-parameter read-only search tool this leaves no material gap for an agent.

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 parameters are documented in the schema and the baseline is 3. The description adds a small amount on top: 'up to 25 matches' reinforces the limit maximum, and the keyword list models the style of query expected. It adds nothing about the 2-character minimum or query length limit, so it is above baseline but not fully additive.

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 opens with a specific verb and resource ('Searches the EconDash catalogue by keyword') and enumerates the domains covered, so an agent knows exactly what is searchable. It also distinguishes itself from retrieval siblings by stating that the returned slug is the input for get_indicator_series, compare_countries and get_indicator_details.

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 states the triggering condition explicitly: 'Use it when the user asks for a statistic for a country or region: its latest value, history or a comparison.' It also gives negative guidance — no individual shares, cryptocurrencies (except the Fear & Greed Index), tax rates, steel or the Baltic Dry Index — so the agent can rule the tool out rather than issue a doomed query.

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