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

Annotations declare readOnlyHint=true, openWorldHint=true, idempotentHint=true, and destructiveHint=false. The description reinforces this by describing a read-only telemetry tool. It adds substantial behavioral context beyond annotations: snapshots are written on cache-miss, history is bounded by a 60-day TTL, gaps in snapshot_dates mean no scan occurred, decay is computed from daily closes (not intraday), and the sign of edge_pp_net indicates trade direction. There is 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 long but densely informative. Every major sentence contributes to either purpose, usage, response format, or limitations. It is organized into implicit sections (purpose, args, response, limits), though without explicit line breaks. There is some redundancy with schema and annotations, but the additional context justifies the length. It is appropriately sized for a tool with no output schema and moderate complexity.

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 that there is no output schema, the description takes full responsibility for explaining the return value. It describes the structure of the response (tracked[], expired[], snapshot_dates[]), the fields within each array, and relevant metrics (trend, decay_pp_per_day, lifespan_days). It also covers edge cases such as snapshot gaps, TTL limits, and the interpretation of edge sign. This is a complete explanation for an analytics tool.

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?

Both parameters are fully described in the input schema (100% coverage), so the baseline is 3. The description repeats the default and clamp values for 'days' and the default for 'window', adding little semantic information beyond the schema. It does frame 'days' as a lookback and 'window' as a snapshot family, but these concepts are already present in the schema descriptions. Thus, no significant added 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 opens with a precise statement: 'Edge persistence and decay telemetry built from daily polymarket_edges snapshots.' It then poses the exact question it answers ('how long has this edge existed and is it shrinking?'), which clearly distinguishes it from sibling tools like polymarket_edges (which likely provides current edge values) and other market tools.

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 explains the use case by contrasting fresh wide edges versus old wide edges, indicating this tool is for longitudinal analysis of edge persistence. It implies this is the right tool when temporal context matters, but it does not explicitly name alternative tools or state when not to use it. Nonetheless, the context is clear enough for an agent to make a reasonable selection.

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