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

Annotations declare readOnlyHint, openWorldHint, idempotentHint, destructiveHint=false, so the safety profile is already known. The description adds substantial behavioral context beyond annotations: snapshots are written on cache-miss, gaps mean no scan happened, history is bounded by a 60-day TTL, decay is computed from daily closes not intraday, and edge_pp_net is signed by trade direction. This goes far beyond the structured hints.

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 long but well-structured with clear labels (Args, RESPONSE, LIMITS) and each section earns its place. It front-loads the core purpose in the first sentence and then provides dense, relevant details about response shape and limitations. No filler or repetition.

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?

There is no output schema, so the description carries the full burden of explaining return values. It thoroughly documents tracked[] with fields (edge_pp_net time-series, first_seen, trend, decay_pp_per_day), expired[] with lifespan_days, and snapshot_dates[]. It also addresses edge cases like gaps and TTL limits. For a tool with this complexity, the description 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 coverage is 100% and the schema already documents both parameters with defaults and allowed values. The description restates days as 'lookback, default 14, max 30' and window as 'snapshot family, default 1wk' without adding new meaning beyond the schema. It does add some context in the response section (e.g., how window selects the snapshot family), but the parameter descriptions themselves are mostly redundant.

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 clearly answers what the tool does (tracks edge persistence/decay over time) and differentiates it from the sibling polymarket_edges tool, which likely provides current snapshots rather than historical trend analysis. The examples ('a fresh wide edge vs. a 3-week-old wide edge') further sharpen the purpose.

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 the question is 'how long has this edge existed and is it shrinking?' It also implies alternatives by noting it is built from polymarket_edges snapshots, subtly distinguishing it from the current-edge view. However, it does not explicitly say 'use polymarket_edges for current edges instead' or list other exclusions, so it stops short of a 5.

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