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

The description goes well beyond the annotations (readOnlyHint, idempotentHint, etc.) by disclosing data limitations: 60-day snapshot TTL, availability starting from when snapshotting was enabled, gaps meaning no scan, and decay computed from daily closes not intraday. It also explains the meaning of negative edge values. This is rich behavioral context that helps the agent anticipate edge cases.

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 structured with clear labels (Args, RESPONSE, LIMITS) and front-loads the core question. Every sentence adds value: it defines the tool's purpose, parameter semantics, response format, and data limitations without fluff. The use of capitalization for response fields aids parsing.

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 fully explains the response structure (tracked, expired, snapshot_dates) and provides interpretation guidance ('median lifespan is your competition clock'). It also covers history depth and computation method. Given the tool's complexity, this is complete and actionable.

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% and the description reinforces both parameters with defaults and interpretation ('days' lookback with max, 'window' snapshot family). It adds the concept of 'snapshot family' and clarifies how negative edge_pp_net maps to trade direction. While the baseline for high schema coverage is 3, the description adds enough nuance to warrant a 4.

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 specific verb+resource: 'Edge persistence and decay telemetry built from daily polymarket_edges snapshots.' It explicitly states the question it answers ('how long has this edge existed and is it shrinking?') and contrasts fresh vs. old edges, which clearly distinguishes it from siblings like polymarket_edges that likely show current edges.

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: it is for assessing edge persistence and decay, with the example that a 3-week-old wide edge is a different trade than a fresh one. It also explains what expired opportunities and median lifespan reveal. However, it does not explicitly name alternative tools or state when not to use it, so it stops short of a full 5.

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