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

Annotations already provide readOnlyHint=false, destructiveHint=false, openWorldHint=true, idempotentHint=false. The description adds valuable context beyond annotations: 'without exposing raw vessel identities or claiming official Canal queues' and mentions a 'human review action' and pricing. This gives the agent behavioral insight without contradicting 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?

The description is two sentences, front-loads the primary action, then lists outputs and caveats. It includes pricing and the payment rail without unnecessary words. Every clause adds value, making it appropriately concise and well-structured.

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, the description carries the burden of explaining what the agent will receive. It lists eight distinct output aspects (side imbalance, movement, dwell, baseline change, freshness, confidence, gaps, human review action) and important constraints (no raw identities, no official queue claim). It does not describe exact return structure, but for a tool of this complexity it is reasonably complete.

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 description adds no parameter-specific meaning beyond what the schema already provides, but the schema's per-parameter descriptions are rich enough to fully explain parameters like sourceMode and identitySalt.

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 clearly states the tool's function: 'Compare aggregate commercial-vessel pressure across two fixed Panama Canal approach zones.' It lists specific outputs (side imbalance, movement, dwell, baseline change, etc.) and distinguishes itself from sibling tools by focusing on Panama Canal zones and emphasizing it doesn't claim official queues.

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 implies its use case (Panama Canal queue/transit monitoring) and mentions it uses fixed approach zones with no custom coordinates, but it does not explicitly state when to use this tool versus alternatives or provide exclusions. Sibling tools are not referenced, so the agent must infer when this is the right choice.

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