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

Annotations declare readOnlyHint=true, so the safety profile is already known. The description adds context that the data is historical and that every figure includes a sample size, which are useful behavioral details. It does not contradict the annotations and adds some value beyond them, though it could be more explicit about output structure.

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 description is only a few sentences but includes a confusing opening ('Free, and how you read meaning into a phase') that adds no value and detracts from clarity. The key information is present, but the structure is not tight and the phrasing is awkward. It could be significantly more concise and 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 read-only stats tool with no parameters and no output schema, the description gives a good sense of what is returned: next-step tendencies, continuation rates, reward vs. drawdown, and sample sizes. It also mentions the historical nature and pairing advice. Minor gaps include not explaining what 'Free' means or how the stats are formatted, but overall it is sufficiently complete for an agent to understand the tool's value.

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?

The tool has zero parameters, so the baseline is 4. The description does not need to explain any parameters, and the schema confirms no inputs are required. No additional parameter semantics are necessary.

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 conveys that the tool provides statistical insights about phases (what happens next, continuation rates, reward vs. drawdown, sample sizes), built from historical Bitcoin data. However, the opening phrase 'Free, and how you read meaning into a phase' is confusing and undermines clarity. It does name a specific resource (phase resolution stats) and distinguishes itself from live per-coin data, but the purpose is not stated as a crisp verb+resource.

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?

The description advises pairing with trendvane_get_phase and clarifies that it is a historical behavior model rather than live data, which helps an agent know when to use it (for historical context) and when not (for live data). It does not explicitly list alternatives or exclusion conditions beyond the live-data caveat, so guidance is present but not comprehensive.

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