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

Annotations already declare readOnly, openWorld, idempotent, and non-destructive, and the description adds extensive behavioral context: snapshots are written on cache-miss so gaps occur, history is bounded by a 60-day TTL, decay uses daily closes net of default slippage, and expired opportunities are detailed with lifespan. No contradiction 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 front-loaded with the core question and example, then structured into Args, RESPONSE, and LIMITS sections. Despite being long, every section earns its place by explaining behavior that is not obvious from the schema or annotations, making it appropriately sized for a telemetry tool with no output schema.

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 documents the return structure: tracked[] with fields, expired[] with lifespan_days, and snapshot_dates[] with explanation of gaps. It also covers limitations (TTL, daily closes, net slippage), making the tool safe to invoke without additional context.

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%, so baseline is 3. The description adds conceptual meaning by calling days a 'lookback' and window a 'snapshot family,' which clarifies how parameters relate to the data collection process. It also notes defaults ('default 14, max 30') that align with the schema, reinforcing but not merely repeating it.

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 a specific purpose: 'Edge persistence and decay telemetry' that answers 'how long has this edge existed and is it shrinking?' It distinguishes itself from the sibling polymarket_edges by focusing on historical persistence rather than current edges, and uses a concrete example to illustrate the distinction.

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 gives clear context for when to use this tool—when you need to know edge persistence and decay. It implicitly contrasts with polymarket_edges by saying it is 'built from daily polymarket_edges snapshots,' and notes that a fresh wide edge is a different trade from a 3-week-old one. However, it does not explicitly name alternatives or state when not to use this tool.

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