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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false. The description adds valuable behavioral context: snapshots are written on cache-miss, gaps mean no scan that day, history bounded by 60-day TTL, and decay computed from daily closes. No contradiction with 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 front-loaded with the core purpose and question it answers. It is fairly long but every sentence contributes necessary detail about the response structure and limitations. While not overly verbose, it could be slightly more concise without losing meaning.

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?

Given no output schema, the description extensively explains the response structure with detailed fields (tracked, expired, snapshot_dates including first_seen, trend, decay_pp_per_day, etc.). It also covers limitations like 60-day TTL and snapshot gaps. This fully compensates for missing output schema.

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 has 100% coverage with basic descriptions for both parameters (days, window). The description adds meaningful context: explains 'days' as lookback with default 14 and max 30 (clamp 2-30 in schema), and 'window' as snapshot family with default '1wk'. It also clarifies how parameters affect the response structure (e.g., snapshot_dates depend on days). Some redundancy but adds value beyond 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 provides 'edge persistence and decay telemetry built from daily polymarket_edges snapshots' and answers the specific question of how long an edge has existed. It differentiates from sibling tools by focusing on persistence/decay rather than raw edges (polymarket_edges) or arbitrage (polymarket_arbitrage).

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 implies when to use the tool (e.g., 'a fresh wide edge and a 3-week-old wide edge are different trades') and provides context about snapshots and data gaps. However, it does not explicitly state when not to use it or name alternative tools for comparison.

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