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

Annotations already declare readOnlyHint=true and destructiveHint=false, so no safety contradiction exists. The description adds a meaningful behavioral fact: 'No API key required,' clarifying that the endpoint is public and does not require authentication. This goes beyond the annotations and helps the agent set correct expectations.

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 core definition is concise and front-loaded: one sentence names the tool's purpose and primary outputs, and a second sentence clarifies authentication. The 'Star the repo' line is promotional and not operational, which prevents a perfect score, but the description remains short and scannable overall.

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 tool with two optional parameters and no output schema, the description lists the key returned metrics, covers the auth requirement, and relies on the schema for parameter details. It is complete enough for successful selection and invocation, though exact output shapes and any edge cases are not described.

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 the parameters' meaning is already fully documented. The description adds minimal extra parameter context: it reinforces that apiKey is optional/not required, but it does not enrich the semantics of the 'days' parameter beyond what the schema states.

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 uses a specific verb and resource ('Get aggregated performance') and enumerates concrete outputs: hit rate, average ROI per signal, average leverage, and breakdown by direction. The word 'aggregated' sharply distinguishes this from sibling tools like get_signal and get_signals, which operate on individual signal data.

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?

Usage context is implied: the word 'aggregated' and the focus on performance stats suggest this tool is for summary-level queries rather than individual signals or signal history. However, the description does not explicitly state when to use get_stats versus alternatives such as get_signal or get_signals, nor does it name any exclusions or alternative tools.

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