Factor board: what followed days like today across recorded metrics

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

Beyond the readOnlyHint and openWorldHint annotations, the description discloses the n >= 30 gate, the median 7-day BTC move vs base rate, and that results are distributions rather than forecasts. This gives the agent meaningful expectations about the output without contradicting annotations.

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?

Two dense sentences lead with use cases and then describe the output format and qualifications. Every clause carries useful information, and the 'distributions, not forecasts' phrase is a compact yet critical disambiguation.

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?

With no parameters and no output schema, the description fully carries the burden of explaining what the agent will receive: every recorded metric, its historical band, median 7-day BTC move, base rate comparison, and sample-size gate. This is sufficient for a no-argument read-only tool.

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 input schema has zero parameters and 100% coverage, so there is no parameter semantics for the description to add. A baseline of 4 is appropriate because the tool takes no arguments and the description cannot meaningfully elaborate on inputs.

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 states a specific resource ('factor board') and the exact function: returning recorded metrics in their historical band with the median following BTC move. It distinguishes itself from siblings by emphasizing a cross-metric conditional overview and explicitly noting 'distributions, not forecasts.'

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 gives explicit trigger scenarios: unusual-band indicators, historical precedent for BTC moves, or cross-metric conditional overview. It does not name specific sibling alternatives or say when not to use this tool instead of another, but the 'not forecasts' clause offers a mild exclusion.

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