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

Annotations already declare read-only, idempotent, and non-destructive behavior; the description adds substantial non-obvious context beyond them: 60-day snapshot TTL, snapshot gaps due to cache-miss scanning, decay computed from daily closes (not intraday), and a detailed explanation of expired[] vs tracked[]. This far exceeds the baseline and enriches the agent's understanding of edge cases.

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 well-structured with explicit RESPONSE and LIMITS sections, making it scannable. Every sentence contributes semantically (field meanings, TTL, gap causes). It earns a 4 rather than 5 because it could be tightened without losing critical detail, but it is far from bloated.

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 return shapes: tracked[] with fields (edge_pp_net timeseries, first_seen, trend, decay_pp_per_day), expired[] with lifespan_days, and snapshot_dates[] with gap explanation. It also covers data limitations (TTL, snapshot start time) and computation basis. This is a complete and self-sufficient explanation for the agent.

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 documents both parameters with descriptions, including defaults and allowed values, so baseline is 3. The description repeats the defaults and adds only the phrase 'snapshot family' to frame window, but this is already in the schema. There is also a minor inconsistency: description says max 30 for days, while schema says clamp 2-30, which is a slight loss of precision.

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?

Uses a specific verb (tracker) and resource (polymarket edge snapshots) while clearly stating it measures edge persistence and decay. The phrase 'how long has this edge existed and is it shrinking?' crisply defines the tool's purpose and implicitly differentiates it from sibling polymarket_edges, which likely shows current edges.

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?

Provides clear context: use when evaluating edge age/trend, and illustrates the difference between fresh vs. old edges ('a 3-week-old wide edge is wide for a reason nobody is willing to take'). However, it does not explicitly name alternatives or state when not to use this tool, so it stops short of full disambiguation.

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