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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false. The description goes further by disclosing behavioral nuances: snapshots are written only on cache-miss (gaps mean no scan), history depth is bounded by 60-day TTL, and decay is computed from daily closes, not intraday. These details are not present in annotations and add significant value.

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 densely packed with relevant information. It front-loads the core purpose and then systematically covers arguments, response fields, and limitations. Every sentence adds value, though a more compact rewriting could improve scannability.

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 fully compensates by detailing the response structure (tracked[], expired[], snapshot_dates[]) and explaining edge cases (snapshot gaps, TTL limits, signed edge values). It also notes the median lifespan as a 'competition clock', providing practical interpretational context. The tool has no required parameters and is read-only, so the description is sufficiently complete.

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 already covers both parameters with descriptions, so baseline is 3. The description adds context by explaining days as 'lookback' with default 14/max 30 and window as 'snapshot family' with default '1wk'. It also clarifies how parameters affect the response (e.g., lookback over snapshot dates). Slight note: description says max 30 while schema says clamp 2-30, but this doesn't materially reduce value.

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?

Purpose is explicitly stated: 'Edge persistence and decay telemetry built from daily polymarket_edges snapshots' and the key question it answers: 'how long has this edge existed and is it shrinking?' This clearly distinguishes it from sibling tools like polymarket_edges by focusing on history/trend rather than current edge detection.

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 context for when to use: 'a fresh wide edge and a 3-week-old wide edge are different trades (the latter is wide for a reason nobody is willing to take)', implying it should be used to assess edge persistence before trading. It does not explicitly name alternatives or when-not-to-use, but the use case is clear enough.

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