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

Annotations already indicate read-only and idempotent behavior, so the description adds substantial context beyond that: the 60-day TTL, snapshot gaps (cache-miss writes), and that decay values come from daily closes not intraday. It also details the response structure, explaining what the agent should expect regarding tracked, expired, and snapshot_dates.

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 well-structured with Args, RESPONSE, and LIMITS sections. It front-loads the purpose and uses a concrete example to convey the tool's value. Some prose (e.g., 'the latter is wide for a reason nobody is willing to take') is illustrative rather than strictly necessary, but it earns its place by conveying the analytical mindset.

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 format (tracked[], expired[], snapshot_dates[]) and their semantics, plus critical limitations (TTL, snapshot gaps, slippage). It covers all aspects needed for an agent to use the tool correctly: purpose, args, response, and edge cases.

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 coverage is 100% (both params documented). The description repeats the defaults and families ('days (lookback, default 14, max 30), window (snapshot family, default 1wk)') but adds little meaning beyond the schema's existing descriptions. The baseline of 3 applies because the description doesn't compensate or expand on the schema.

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+resource ('answers how long this edge existed...') and distinguishes itself from sibling tools like polymarket_edges by focusing on historical persistence and decay rather than current edge computation.

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?

It provides explicit use cases ('Answers how long has this edge existed and is it shrinking?') and explains the relationship to polymarket_edges snapshots. While it doesn't name alternative tools explicitly, the context makes it clear this is for historical analysis. Missing explicit 'when not to use' guidance, but the purpose is well-defined.

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