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

Annotations declare readOnlyHint=true and idempotentHint=true; the description adds significant behavioral detail: snapshots are written on cache-miss, gaps mean no scan, decay uses daily closes net of slippage, history bounded by 60-day TTL, and the signed nature of edge_pp_net with SELL YES negative. No contradictions with 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-structured: core purpose, args, response breakdown, and limits. Each sentence carries substantive information (e.g., 'the median lifespan is your competition clock'), and it's front-loaded with the key question it answers.

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 thoroughly details the response structure (tracked[], expired[], snapshot_dates[]) and explains edge cases (snapshot gaps, TTL, intraday vs daily closes). For a 2-param read-only tool, this is 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 description coverage is 100%: both 'days' and 'window' are fully described in the schema. The description repeats 'days (lookback, default 14, max 30)' and 'window (snapshot family, default 1wk)' without adding new meaning beyond the schema, so baseline 3 applies.

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 'Edge persistence and decay telemetry built from daily polymarket_edges snapshots' and explicitly frames the tool's question: 'how long has this edge existed and is it shrinking?'. This gives a specific verb and resource, clearly distinguishing it from siblings like polymarket_edges which likely provides current 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 usage context: this is for historical persistence/decay analysis, not current edges, and even illustrates a use case ('a fresh wide edge and a 3-week-old wide edge are different trades'). However, it never explicitly names alternatives or says 'use this when...' versus siblings, so it's clear but not explicit about exclusions.

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