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

Annotations already declare readOnlyHint, idempotentHint, and non-destructive behavior. The description adds valuable behavioral context: it avoids using posterior information, restricts conclusions to provided evidence, and explicitly disclaims market-wide coverage. There is no contradiction with annotations.

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?

Two dense, front-loaded French sentences with no filler. Every clause adds meaning: the comparison baseline, the restriction against future data, and the evidence-based limit of conclusions.

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?

Given the output schema exists and annotations cover safety/idempotence, the description explains the core evaluation logic well. However, it omits guidance on the optional materiality threshold and how feasibility values should be interpreted, leaving a small but real completeness gap for a tool with this input complexity.

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 0%, so the description needed to compensate for parameter meaning. It implicitly maps 'contract' and 'alternatives' through its comparison wording, but it says nothing about materiality_eur_year or field-level semantics such as feasibility, validity periods, or comparison_basis. This is a significant gap given the complex nested schema.

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 uses a specific verb ('Compare') and identifies the exact resource: a signed contract against dated, valid, feasible offers available at signing time. It clearly distinguishes the historical-optimality assessment from a general market-wide comparison, making the tool's purpose unambiguous even among siblings.

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 provides clear context: use this tool to compare only offers that were dated, valid, and feasible at signature, and never to claim whole-market coverage. However, it does not explicitly name alternatives or state when not to use the tool relative to siblings like assess_ppa or renewal_advisor, so it stops 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.