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

Annotations only declare read-only, idempotent, and non-destructive properties. The description adds substantial behavioral context: the 60-day snapshot TTL limits history depth, snapshots are written only on cache-miss (gaps indicate no scan), and decay is computed from daily closes of edge_pp_net (net of default slippage), not intraday. This goes well 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 lengthy but meticulously structured: it opens with purpose, then details the args, response fields (tracked[], expired[], snapshot_dates[]) each with clear explanations, and ends with limits. Every sentence serves a purpose, and bold labels improve parseability for agents. It is as concise as the complexity allows.

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?

Since there is no output schema, the description carries full responsibility for explaining return values. It comprehensively describes all three response components, including the time-series, trend and decay fields, lifespan, and snapshot dates. It also covers the TTL and data-gap limitations, making the tool's behavior fully predictable for an 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 coverage is 100% (both params described), so the baseline is 3. The description adds meaning by explaining 'window (snapshot family)' and clarifying days as 'lookback' with 'max 30' vs schema's 'clamp 2-30'. While the min clamp is omitted in the description, the overall context adds value without contradicting the schema.

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 opens with a clear statement of the tool's role: 'Edge persistence and decay telemetry built from daily polymarket_edges snapshots.' It further answers a specific question ('how long has this edge existed and is it shrinking?') and explicitly differentiates from the sibling polymarket_edges tool by focusing on historical snapshot analysis rather than current edge generation.

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 usage context by contrasting fresh vs. old edges ('a fresh wide edge and a 3-week-old wide edge are different trades'), making clear when this tool should be used. However, it does not explicitly name alternative tools or provide exclusion criteria, so it falls short of a 5.

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