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

The description goes well beyond the annotations (readOnlyHint, openWorldHint, idempotentHint, destructiveHint) by detailing data source, snapshot behavior (cache-miss writes), TTL limits, decay computation method (daily closes of edge_pp_net, not intraday), and interpretation of gaps in snapshot_dates. It also explains the meaning of expired[] opportunities and the 'competition clock'. This is rich behavioral context that fully informs the agent.

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 well-structured with clear sections (Args, RESPONSE, LIMITS) and is front-loaded with the core purpose. It is dense but every sentence contributes useful information, including the explanatory metaphor about the edge being wide 'for a reason nobody is willing to take'. However, it contains some redundancy (e.g., repeating 'snapshot' frequently) and could be slightly tightened without losing value.

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 provides an extensive account of the response structure (tracked[], expired[], snapshot_dates[]) with field-level details (first_seen, trend, decay_pp_per_day, lifespan_days). It also covers limitations (60-day TTL, snapshot start time, daily closes). This is exceptionally complete for a telemetry tool with two parameters and no output schema.

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?

The schema has 100% description coverage for both parameters (days and window), so the baseline is 3. The description repeats the defaults and meaning ('days (lookback, default 14, max 30)', 'window (snapshot family, default "1wk")') but does not add new semantics beyond what the schema already provides. The schema already includes clamping details and allowed values for window, so the description adds minimal extra value.

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 the tool's purpose: edge persistence and decay telemetry built from daily polymarket_edges snapshots. It answers a specific question ('how long has this edge existed and is it shrinking?') and distinguishes itself from the sibling polymarket_edges tool by focusing on historical tracking rather than current edges. The verb 'Answers' and resource definition make it unambiguous.

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 the tool: when you need to know edge persistence, decay, or whether an edge is aging. It mentions 'a fresh wide edge and a 3-week-old wide edge are different trades', which implies a use case for evaluating edge quality over time. However, it does not explicitly mention alternatives or exclusions (e.g., 'use polymarket_edges for current edges'), so it lacks explicit when-not-to-use guidance.

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