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

Annotations already declare readOnly/idempotent/non-destructive behavior, so the description meaningfully adds behavioral details beyond that: history is limited by a 60-day snapshot TTL, snapshots only exist on cache-miss days, edge_pp_net is signed by trade direction, and decay uses daily closes rather than intraday data. This is rich, non-obvious behavior disclosed clearly. 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 longer than ideal but is well-structured with ARGS, RESPONSE, and LIMITS sections, and the opening line quickly states the core purpose. Each sentence adds substantive value—response format, edge cases, TTL constraints—so despite its length, it is efficient for a tool with this complexity.

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 the absence of an output schema, the description fully documents the response structure (tracked[], expired[], snapshot_dates[]), explains field semantics and edge cases (TTL, cache gaps, signed values), and clarifies computation. The tool is complex and the description covers all essential operational aspects, making it effectively self-contained for agent invocation.

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% and already documents both parameters (days with default/clamp, window with allowed values). The description mostly repeats these details and adds only modest context like 'snapshot family' and the lookback purpose. Since the schema carries the parameter meaning, the description adds marginal value, matching the baseline of 3 for high schema coverage.

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 defines the tool's purpose as 'edge persistence and decay telemetry' and frames it around a specific question: 'how long has this edge existed and is it shrinking?' It distinguishes itself from the sibling polymarket_edges tool by emphasizing temporal edge decay vs. current edge data, including the concrete contrast between a fresh wide edge and a 3-week-old one.

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 provides clear context for when to use this tool: when the user needs to understand edge persistence and decay over time, not just current edges. It implies the alternative is polymarket_edges (current snapshot) but does not explicitly state 'use X instead' or describe exclusion scenarios. The guidance is implied through the telemetry framing rather than explicit when-not-to-use instructions.

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