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

Annotations declare a non-read-only, open-world, non-idempotent operation, so the description needn't restate safety. It adds some value by disclosing that similarity/agreement metrics are produced only 'when measurable', but omits the resource cost (multi-engine dispatch, one deep solve per day) and what state the non-read-only nature touches.

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?

A single tight sentence with the core action front-loaded and no filler. It is appropriately short, though the brevity is also the source of its usage-guidance gap.

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 no output schema and a non-read-only, quota-bearing operation, the description should explain what the comparison result contains and what the call costs or consumes. It leaves the return shape and resource implications unstated and does nothing to separate this tool from its crowded set of siblings.

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 depth, model, query, and antagonist are all fully documented in the schema, including the quota and enum refusals. The description adds no parameter meaning beyond that, so the 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 (compare) and resource (answers from configured engines), plus the analytical angle (inspect disagreement). Clear enough for an agent to grasp intent, but it does not distinguish itself from closely related siblings like ecca_bts_divergence, ecca_decision_tournament, or ecca_verify.

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 purpose but no when-to-use, when-not-to-use, or alternative routing guidance. With four overlapping comparison/verification siblings, an agent has no basis for choosing this tool over ecca_bts_divergence or ecca_decision_tournament.

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