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

Annotations already declare readOnlyHint, openWorldHint, and idempotentHint. The description goes well beyond by explaining snapshot TTL limits, cache-miss writing behavior, decay computed from daily closes not intraday, and the meaning of date gaps. It also uses 'LIMITS' to disclose boundaries, which adds rich behavioral context 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?

The description is well-structured with clearly segmented parts: purpose, args, response, and limits. It is dense but every sentence earns its place—no filler or repetition. The front-loaded purpose sentence immediately conveys the tool's unique value.

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 thoroughly explains the return structure (tracked[], expired[], snapshot_dates[]) including field-level semantics and the meaning of trend values. It also covers limitations (snapshot TTL, start date, daily closes), making the tool's behavior fully understandable for an agent to select and invoke it.

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?

Both parameters (days and window) are already described in the input schema, so the baseline is 3. The description adds meaningful context by explaining that 'days' is a lookback across snapshot history, not just calendar days, and that 'window' selects a snapshot family. It also clarifies how these parameters affect the response structure (e.g., tracking across prior snapshots).

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 opens with 'Edge persistence and decay telemetry built from daily polymarket_edges snapshots,' which clearly identifies the tool's specific function and scope. It distinguishes itself from sibling tools by focusing on historical persistence and decay rather than current edge values, answering 'how long has this edge existed and is it shrinking?' This is a specific verb+resource+scope definition.

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 clear context for when to use the tool: when you need to understand edge persistence and decay over time, especially the distinction between fresh and old edges. It implies the use case but does not explicitly name alternative tools or state exclusions (e.g., 'for current edges use polymarket_edges'), so it lacks explicit when/when-not guidance.

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