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

Beyond the annotations (readOnlyHint, idempotentHint, destructiveHint false), the description adds meaningful behavioral detail: it reads the most recent public snapshot and explicitly indicates when no recent data is available. This informs the agent about data freshness handling.

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 a single, tight sentence that front-loads the essential data (market, contracts, source) and adds the no-data behavior without filler. Every phrase earns its place.

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, safe annotations, and one clearly documented optional parameter, the description fully covers source, content, and availability behavior. Nothing critical is missing for an agent to invoke the tool correctly.

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?

The schema already documents the single optional parameter 'asof' with ISO format and default value, so schema coverage is 100%. The description adds no additional parameter-level meaning, which matches the baseline of 3 for high schema coverage.

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 ('Lit') and resource ('Courbe forward EEX France' with defined contracts CAL Y+1, CAL Y+2, M+1). It clearly distinguishes itself from the sibling tools, which all concern invoices, PPAs, or analyses rather than market data.

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 clear context: this tool retrieves the latest EEX forward curve from market_observation. Although it does not explicitly name alternatives or exclusion conditions, no sibling tool provides similar market data, so the intended use case is obvious and unambiguous.

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