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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the description's main added value is the 'cost: free' note and the constraint that results are limited to platform-supported instruments. It does not disclose matching behavior (substring vs exact), result limits, or ranking.

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 compact sentence, front-loaded with a category tag and ending with the cost note. Nothing is redundant, though the brevity leaves room for a short clarifying clause about matching behavior.

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 simple single-parameter read tool with annotations and full schema coverage, the description covers purpose, scope, and cost. It is adequate but thin: with no output schema, it gives no hint about what a match result contains or how ambiguous keywords are handled.

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 the single query parameter is already documented in the schema. The description repeats the same 'keyword like BTC' example, adding no syntax, case-sensitivity, or matching details 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?

The description gives a specific verb and resource: search platform-supported trading instruments (coins/pairs). It is clear enough to distinguish from siblings that quote prices or return tickers, though it does not name those siblings explicitly.

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?

There is no statement of when to use this tool versus alternatives such as platform_market_quote or platform_market_ticker, nor any prerequisite or follow-up guidance. An agent must infer that this is a symbol-resolution step before other market calls.

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