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

Annotations already cover the safety profile (readOnlyHint=true, destructiveHint=false, openWorldHint=true), but the description adds genuinely non-structured behavior: results are public without a key, an API key unlocks additional ROI metrics, and byMonth returns a specific month set. It does not mention rate limits or response size, which keeps it short of a 5.

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 what is aggregated and returned, followed by usage routing and the public/key distinction; every sentence carries information. The first sentence is dense with em-dash clauses and metric lists, which slightly slows parsing but wastes no words.

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 output schema, the description carries the return-value burden and does so by enumerating hit rate, verified count, average leverage, direction breakdown, and the key-gated ROI figures. It also covers auth behavior, the public fallback, and the sibling tools, leaving no material gap for a 2-parameter read 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?

Schema description coverage is 100%, so both parameters are already documented, including the 1–90 range and the default of 30. The description restates the default and the apiKey tiering but adds no syntax or semantics beyond the schema, so the baseline of 3 applies.

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?

Names a specific verb+resource (aggregate performance stats of resolved signals in a lookback window) and enumerates the returned metrics, so the agent knows exactly what it computes. It also explicitly distinguishes itself from get_signals and get_signal_history by stating it returns no individual signals.

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 decision rule ('Use it to judge recent reliability before acting') and names the alternatives to use instead when individual signals are needed. The public/no-key and with-key tiers are also spelled out, so the agent knows when extra value is available.

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