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

The annotations already mark this as read-only. The description adds valuable context beyond annotations: it is a paid call, and it clarifies that 'boundary' is settled and won't change while 'updates' is still forming. No contradiction with readOnlyHint.

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?

Three sentences, each earning its place: the operation, the paid-call warning, and the two parameter decisions. No filler, and the core purpose is front-loaded.

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 read-only call with full schema coverage, the description covers the core operation, the paid nature, and the meaningful distinction between the two kinds of readings. It does not describe the response shape, but with no output schema and an understandable 'get phase' return, this is a minor gap.

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% and the schema already documents all three parameters. The description still adds practical guidance, especially around the default behavior for 'tf' (omitting it or setting it to 'all') and the settled-versus-live distinction for 'kind'.

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 current market phase for one coin'. The phrase 'for one coin' clearly separates this from sibling tools like trendvane_list_phase_meta or trendvane_compose_phases.

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 clear operational context: the call is paid, and it explains when to use 'boundary' versus 'updates' and how to request all timeframes. It does not explicitly name sibling alternatives or say when not to use the tool, so it misses the top score.

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