scan_market_regimes

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

Annotations already declare readOnlyHint=true, openWorldHint=true, destructiveHint=false, so the safety profile is covered. The description nonetheless adds real behavioral context beyond them: the billing model (one call per returned row, non-matching coins free), the refusal-with-alternatives behavior, and the snapshot/closed-bar freshness semantics. However, it asserts the venue is 'sampled on Binance, Bybit, OKX and Bitget' while the exchange enum exposes 15 venues, leaving the actual sampled set ambiguous.

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-loaded with purpose and regime vocabulary, then transitions to data source, billing, and the sibling alternative in a logical order. It is dense and slightly long for a single paragraph, but every sentence carries information an agent needs (regimes, fields, billing, alternative).

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 15-parameter, zero-required screening tool with no output schema, the description compensates by naming the return columns (confidence, trend strength, ADX, volatility ratio, regime age), the billing consequence, and the refusal path. Nothing essential to correct invocation is missing.

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% across all 15 parameters, so the schema already carries the semantics and a baseline of 3 applies. The description restates the regime labels and the venue/timeframe constraint but adds no syntax, default, or interaction detail beyond what the schema documents.

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 (screens) and resource (crypto perpetual futures venue by market regime), enumerates the four regime labels it filters on, and lists the returned fields. It also explicitly distinguishes itself from the sibling get_market_regime ('live single-coin read'), so an agent can route 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?

Gives an explicit alternative and the condition that selects it: use get_market_regime 'for a live single-coin read with cross-venue funding.' It also states when the tool will refuse (unsupported venue or timeframe) and that the alternatives are returned, so failure behavior is anticipated rather than inferred.

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