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

Goes well beyond the readOnly/openWorld/idempotent annotations: it discloses cost (free, no payment required), caching behavior, data provenance (named public source, never curated), and the semantics of the 'quality' field real vs degraded on a failed refresh. It also explains the tri-state 'askable' flag and that null means the venue could not be read rather than a false negative.

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 the core purpose and dataset scope, and the routing distinction ('NOT the ask authority') appears early. It is dense but a few parenthetical clauses (e.g. 'never a lie in either direction') cost more words than they add.

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?

An output schema exists, so return structure needn't be restated, yet the description still contextualizes the derived 'askable' and 'quality' fields usefully. Cost, caching, freshness and dataset origin are all covered; only the limit range/bounds remain unexplained.

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 0%, so the description carries the load: it reveals the default of 50 ('top 50 by default'), which the schema does not. However, it never mentions the maximum of 250 or the valid range for 'limit', leaving part of the single parameter's semantics undocumented.

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+resource (market-cap list of the largest coins, rank-ordered with market cap, price and 24h change) and explicitly scopes it as the DISCOVERY list rather than the ask authority. An agent can distinguish it from siblings like tollbridge_call without opening either 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?

Clearly frames when to use it ('the DISCOVERY list a user picks a subject from') and when not ('it is NOT the ask authority'), which is the key routing decision. It does not name the alternative tool explicitly (e.g. tollbridge_call), so the exclusion is implied by role rather than by name.

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