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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and not destructive. The description adds valuable behavioral details: data comes from daily snapshots with 60-day TTL, gaps exist when scans don't occur, decay is computed from daily closes (not intraday), and trend/decay calculations are based on absolute edge_pp_net. No contradictions.

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 thorough but not overly verbose. It starts with the core purpose, then details the response structure and limits. Every sentence provides distinct value, though the response format explanation is quite detailed. Could be slightly more concise, but it's well-organized.

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 comprehensively explains the response: tracked[], expired[], snapshot_dates[] with field meanings (first_seen, trend, decay_pp_per_day, lifespan_days). It also covers data freshness (60-day TTL), snapshot gaps, and computation details. Parameter semantics are clear. No missing context.

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% for both parameters. The description adds context: default values (14 days, '1wk'), range for days (clamp 2-30), and clarifies that window is a snapshot family. This goes beyond the schema's parameter descriptions.

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 from daily snapshots. It answers a specific question ('how long has this edge existed and is it shrinking?') and distinguishes from the sibling polymarket_edges tool by focusing on time-series analysis rather than raw edge values.

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 explains that a fresh wide edge and a 3-week-old wide edge are different trades, implying the tool is for assessing edge quality over time. It doesn't explicitly specify when not to use, but the context makes it clear this is for historical decay analysis rather than current edge discovery.

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