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

Annotations already declare readOnly, idempotent, non-destructive, closed-world, so the safety profile is covered. The description usefully discloses the exact-mode validation limits (12 draw cards, two hands, two discards) and that validation mirrors HTTP, but these limits largely restate the conditional schema and no cost, latency, or result-shape context is given.

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 purpose, and no padding. But 'with the same contract and validation as HTTP' is cryptic and consumes space without conveying actionable meaning.

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?

This is a complex tool with nested objects, conditional schema branches, and no output schema, yet the description is only three terse sentences. With 0% parameter coverage and no return-value explanation, an agent lacks enough to construct a valid call confidently.

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% across 6 parameters, so the description must carry the load. It only clarifies explain_actions and hints at analysis_mode (exact vs immediate); contract_version, budget_score_calls, request_id, and the required state object fields are left entirely to the schema, which does not describe them either.

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 ('all immediate plays or exact small-deck play/discard values'), so the agent knows it enumerates and compares candidate actions. It does not explicitly differentiate itself from the sibling recommend_action, which likely does the same computation but returns a single pick, leaving that distinction to inference.

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?

'Select explain_actions for particular branches' and the mode-specific limit note imply when each mode applies, giving implied usage guidance. However, there is no explicit statement of when to choose this over recommend_action or evaluate_hand, and no stated prerequisites or exclusions.

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