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

Annotations already declare readOnlyHint=true and destructiveHint=false, but the description adds substantial behavioral context: limits on history depth (60-day TTL, snapshot start), the fact that decay is computed from daily closes (not intraday), and the explanation that gaps in snapshot_dates mean 'nobody scanned that day'. This goes well beyond the annotations and provides critical operational transparency.

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 dense but extremely well-structured, with clear sections for the core purpose, arguments, response format, and limits. Every sentence contributes value—no filler. It front-loads the core question and then provides necessary detail in a structured way. This is a model of conciseness for a complex tool.

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?

Despite having no output schema, the description fully specifies the response structure (tracked[], expired[], snapshot_dates[]) and key fields (trend, decay_pp_per_day, lifespan_days). It also covers data caveats (TTL, snapshot gaps, slippage adjustment). This is complete enough for an agent to invoke the tool and interpret results without external knowledge.

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 description coverage is 100%, so the baseline is 3. The description restates the parameters (days, window) with defaults and max values, but does not add new meaning beyond what the schema provides. The RESPONSE section provides context on how parameters affect output, but that is more about output behavior than parameter semantics. Thus a 3 is appropriate.

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' and answers the specific question 'how long has this edge existed and is it shrinking?'. This is a specific verb+resource description that distinguishes it from siblings like polymarket_edges, which likely provides fresh edge scans, by focusing on historical persistence and decay.

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 strong usage context: 'a fresh wide edge and a 3-week-old wide edge are different trades (the latter is wide for a reason nobody is willing to take)'. This clearly implies when to use the tool (to assess edge age/decay before trading). However, it does not explicitly name alternatives or list when-not-to-use scenarios, 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.