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

Even though annotations already declare readOnlyHint=true and idempotentHint=true, the description goes much deeper. It discloses that snapshots are written only on cache-miss, meaning gaps in snapshot_dates[] indicate no scan that day, that history is bounded by a 60-day TTL, and that decay numbers come from daily closes of edge_pp_net, not intraday. These are critical behavioral nuances that annotations cannot convey.

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 long but every sentence earns its place. It is structured into clear sections: the purpose statement, the Args, the RESPONSE layout, and LIMITS. The information is dense yet efficiently organized, with no fluff or repetition. The front-loading of the core question the tool answers is excellent.

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?

There is no output schema, so the description carries the full responsibility of explaining the return value. It thoroughly describes tracked[], expired[], and snapshot_dates[], including the meaning of 'trend', 'decay_pp_per_day', 'lifespan_days', and the signed nature of edge_pp_net. It also states limitations (TTL, snapshot gaps, daily closes). This is a complete and self-sufficient description for a tool of this complexity.

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 already documents both parameters with descriptions (100% coverage). The description adds a little extra by framing 'window' as a 'snapshot family' and enumerating the allowed values, but overall it largely restates schema information. Since schema coverage is complete, the baseline of 3 is appropriate; the description gives marginal additional meaning.

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 clearly states the tool's purpose: 'Edge persistence and decay telemetry built from daily polymarket_edges snapshots.' It uses a specific verb ('tracker') plus resource ('Polymarket Edge') and further distinguishes itself by explaining it answers 'how long has this edge existed and is it shrinking?' This goes beyond a generic statement and differentiates it from sibling tools like polymarket_edges, which likely focus on current edges rather than historical persistence.

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 provides strong contextual guidance: it explains that a fresh wide edge and a 3-week-old wide edge are different trades, implying this tool is for assessing edge maturity. It also mentions the lookback window and snapshot defaults. However, it does not explicitly name alternative tools or state when NOT to use this tool, so it stops short of full exclusionary guidance.

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