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

Annotations already declare readOnlyHint true and destructiveHint false, lowering the bar. The description adds rich behavioral context: snapshots are written only on cache-miss, gaps mean no scan that day, history is bounded by a 60-day TTL, and decay numbers are computed from daily closes of edge_pp_net. These are important non-obvious behaviors that go beyond the annotations.

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 dense but well-organized into purpose, Args, RESPONSE, and LIMITS sections. Every sentence adds value, but it is longer than necessary. The front-loaded question 'how long has this edge existed and is it shrinking?' effectively captures the tool's purpose. It earns a 4 for structure despite slight verbosity.

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 carries the full burden of explaining return values, and it does so comprehensively: tracked[] includes time-series, first_seen, trend, and decay metrics; expired[] includes lifespan_days; snapshot_dates[] explains gaps. It also covers history-depth limits and calculation basis. This is a complete and self-contained explanation for a moderately complex analytical tool.

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 coverage is 100%: both days and window have descriptions including defaults and clamp values. The description repeats these defaults but adds minimal new meaning—primarily introducing the concept of 'snapshot family' for window. Since the schema already fully documents the parameters, the baseline of 3 applies; the description does not substantially enhance parameter understanding.

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 a specific verb and resource: 'Edge persistence and decay telemetry built from daily polymarket_edges snapshots.' It directly answers the question 'how long has this edge existed and is it shrinking?' and clearly distinguishes itself from the sibling tool polymarket_edges by focusing on the historical persistence/decay analysis rather than raw edge data.

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 implies when to use it: when you care about edge age and decay ('a fresh wide edge and a 3-week-old wide edge are different trades'). It also provides contextual constraints in LIMITS (60-day TTL, snapshot gaps) that inform usage. However, it does not explicitly name alternative tools or say 'use X instead', though the sibling list makes the distinction fairly clear.

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