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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint, but the description adds significant behavioral context: snapshot writes occur on cache-miss (so gaps mean no scan), history depth is bounded by a 60-day TTL, and decay numbers are computed on daily closes of edge_pp_net, not intraday. These details go well beyond annotation hints and set proper expectations about data availability and calculation methodology.

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 into clear sections: purpose, args, response, and limits. Every sentence provides useful information, and the use of labels 'Args:', 'RESPONSE:', 'LIMITS:' makes it scannable. It is more verbose than strictly necessary, but the complexity of the response format and caveats justifies the length.

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 must explain return values, and it does so thoroughly: tracked[], expired[], and snapshot_dates[] are each defined with their contents and implications (e.g., median lifespan as 'competition clock'). It also covers historical limitations (60-day TTL, snapshot gaps) and calculation details. Given the tool's complexity, this 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%: both parameters are described in the schema. The description repeats the same info ('days (lookback, default 14, max 30), window (snapshot family, default "1wk")') without adding new semantics beyond what the schema already provides. It does not clarify values, formats, or edge cases, so it meets the baseline but does not elevate 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 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 sibling tools like polymarket_edges by focusing on historical edge tracking rather than 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 implies when to use this tool: when you need to know if an edge is fresh or decaying, comparing 'a fresh wide edge and a 3-week-old wide edge.' It notes it's built from polymarket_edges snapshots, which signals a complementary role, but it does not explicitly name alternatives or state 'use this instead of X.' Clear context but no explicit exclusions.

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