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

Annotations already cover the safety profile (readOnly, idempotent, openWorld, non-destructive), so the bar is lower. The description adds genuinely useful context the annotations cannot: every row carries provenance (live, official schedule, published rule, estimate, user) and the rationale that a block-height-projected halving is less certain than a convention-fixed expiry. It stops short of describing pagination or row shape.

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?

Three sentences, front-loaded with the resource and its contents, then the provenance rule, then the usage directive. The mid-sentence event catalogue is dense but every item earns its place by defining scope; the provenance sentence is somewhat long but carries the tool's main behavioral insight.

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 partially carry return semantics — and it does explain that each row states its date source, plus the confidence framing. It still omits row fields (event name, date, impact label) and pagination behavior, but for a read-only calendar listing with fully documented params this is close to 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 description coverage is 100%, so the schema already documents days, limit, impact and symbol including defaults and caps. The description only loosely reinforces this by mentioning 'the next funding settlements for a contract' (tying to symbol) and by implying a forward horizon (days); it adds no syntax or format detail beyond the schema. Baseline 3 is correct.

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?

Names a specific forward-looking resource (scheduled events) and enumerates the concrete event classes covered — FOMC, CPI, NFP, funding settlements, halving, difficulty retargets, options expiry, CME settlement. The closing line 'nothing else here looks forward' implicitly separates it from the calendar_history sibling without needing to open either schema.

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?

Gives an explicit usage trigger: 'Use it before saying anything about what happens next', which tells the agent exactly when this tool is the right choice. It does not name calendar_history as the retrospective alternative nor state any exclusions, 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.