Get Futures Curve

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

Annotations already declare readOnlyHint=true and openWorldHint=true, and the description aligns with those (a 'Get' operation). Beyond annotations, it adds real behavioral context: the account-entitlement requirement, backward-compatibility behavior for 'contract codes and older venue slugs,' the return composition, and the authority caveat that 'the API response is authoritative.' Not quite a 5 because error behavior when entitlement is missing is not disclosed.

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 front-loaded with the core purpose and every sentence earns its place: purpose, input guidance, compatibility note, return content, prerequisite, and alternative routing. Minor inefficiencies exist: the canonical-slug sentence duplicates the schema parameter description, and the final sentence packs two distinct ideas (routing to opa_get_plans and API authoritativeness) into one clause.

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?

For a low-complexity tool (1 optional parameter, no output schema, no nested objects), the description covers purpose, return values, accepted inputs, compatibility behavior, entitlement prerequisite, and an alternative tool. The remaining gaps are minor: what happens if the account lacks entitlement (error vs. empty response) and how many contract months are returned. Overall it is near-complete given the annotations already cover read-only and open-world semantics.

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 tool description restates the canonical slugs ('brent, wti, gasoil, natural-gas, ttf-gas, lng-jkm, eu-carbon, or uk-carbon') and compatibility inputs, which largely duplicates the schema's own parameter description ('legacy venue slugs remain accepted for compatibility'). No new syntax, formatting, or behavioral nuance is added beyond what the schema already provides.

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 states a specific verb and resource: 'Get the futures forward-curve contracts returned for this account.' The 'forward-curve' qualifier and account scoping help distinguish it from generic siblings like opa_get_futures, and the return content ('available contract months with settlement prices plus market-structure analysis') further specifies the purpose. However, it stops short of explicitly contrasting itself with the closest sibling opa_get_futures.

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?

There is explicit routing: 'Use opa_get_plans for current access and pricing; the API response is authoritative,' which names an alternative and the condition to switch. It also adds the prerequisite 'Requires an eligible account entitlement.' It does not, however, give when-not-to-use guidance relative to the nearest sibling opa_get_futures or data-history alternatives like opa_get_history.

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