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

Annotations already declare readOnly/openWorld/no-destructive, and the description adds real value on top: no API key needed, thin-market exclusion thresholds (24h < 1,000, lifetime < 10,000), the meaning of expiresInMs, and the caveat that endDate is scheduled not settlement. Missing pagination/rate behavior, but the added context is substantial.

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?

Four sentences, each carrying distinct information (scope, filter, row shape, semantic caveat), with the sort order and window front-loaded. No filler.

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 an output schema present, return values need no explanation, yet the description still flags the key derived field (expiresInMs) and the endDate caveat. Nothing material is missing for a read-only listing 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?

Schema description coverage is 100%, so every parameter is already documented in the schema; the description only restates the `days` default (7), adding no syntax or interpretation beyond the schema. Baseline 3 applies.

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?

States a specific verb and resource ('list of OPEN events') with scope qualifiers: endDate within `days`, soonest first, across all venues. It distinguishes itself from pm_data_events/pm_data_resolved by the 'open' + 'expiring soon' framing.

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?

Implicitly sets the use case (upcoming expirations within a lookahead window) and gives the default window, plus the liquidity screen that governs inclusion. It does not explicitly name a sibling alternative or state when NOT to use it, so it falls 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.