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

The annotations already declare readOnly, idempotent, openWorld, and non-destructive traits. The description adds substantial behavioral context beyond that: history depth bounded by 60-day snapshot TTL, snapshots written only on cache-miss (explaining gaps), decay computed from daily closes of edge_pp_net (net of slippage) rather than intraday, and the interpretation of expired[] opportunities. These are valuable specifics that the annotations do not 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 moderately long but well-structured into clear sections: purpose, args, response, and limits. Every sentence adds value, explaining not just what but why (e.g., 'the median lifespan is your competition clock'). It is front-loaded with the core question and then details. The length is justified by the complexity of the tool, though it could be slightly tightened 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 that there is no output schema, the description thoroughly covers the return structure (tracked[], expired[], snapshot_dates[]) with field names and meanings. It also explains data caveats (TTL, snapshot gaps, daily vs intraday) and how to interpret expired opportunities. The tool has only 2 parameters, and the description and schema together fully cover its usage and behavior, making it complete for an agent to select and invoke correctly.

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% (both days and window have descriptions). The description reiterates the parameters (days lookback, default 14, max 30; window family default '1wk') but adds little new semantic meaning beyond what the schema provides. It does clarify that window refers to a 'snapshot family', but that is also in the schema. The baseline of 3 is appropriate since the schema already documents the parameters well.

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 function: 'Edge persistence and decay telemetry built from daily polymarket_edges snapshots.' It answers a specific question ('how long has this edge existed and is it shrinking?') and distinguishes itself from the sibling tool polymarket_edges by focusing on time-series persistence rather than current edge values. The verb 'tracker' and resource 'edge persistence/decay' make the purpose specific and unambiguous.

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 clear context for when to use the tool: when you need to know an edge's lifespan and decay. It contrasts a fresh wide edge with a 3-week-old one, implying this tool is for evaluating edge longevity. However, it does not explicitly name alternative tools or state when NOT to use it, which would warrant a 5. Still, the context is sufficiently clear.

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