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 substantial behavioral context: snapshots are written on cache-miss, gaps mean no scan occurred, history is bounded by a 60-day TTL, and decay uses daily closes not intraday. This goes far beyond the annotations and provides a clear operational model.

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 longer than average but well-organized with uppercase section markers (Args, RESPONSE, LIMITS). It front-loads the purpose statement and each sentence contributes operational detail. It could be trimmed slightly, but the structure makes the information scannable and worth its length.

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 fully specifies the response shape (tracked[], expired[], snapshot_dates[]), explains what each field means (including trend enum and decay_pp_per_day), and covers limitations (TTL, cache-miss gaps, daily-close basis). This is complete for a tool of this complexity, and annotations cover the safety profile.

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 explicit descriptions in the input schema. The description's Args section only restates defaults already present in the schema (e.g., 'default 14', 'default 1wk') and adds the phrase 'snapshot family' which is also present in the schema. It adds no meaningful new parameter semantics beyond what is already structured.

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 as 'Edge persistence and decay telemetry built from daily polymarket_edges snapshots' and phrases the core question it answers: 'how long has this edge existed and is it shrinking?'. This distinguishes it from sibling tools like polymarket_edges, which likely returns current edges, by emphasizing historical tracking and decay analysis.

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 a clear context for when to use the tool ('a fresh wide edge and a 3-week-old wide edge are different trades'), implying it is for assessing edge persistence over time. However, it does not explicitly name alternative tools or state when NOT to use it, 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.