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

Annotations already declare read-only, open-world, idempotent, and non-destructive behavior, so the bar is lower, but the description adds substantial behavioral detail: unscored vessels are not defaulted, silence_hours is measured against the data clock, commodity is ignored, and vessels in stale coverage boxes are voided and never ranked. This is far beyond what annotations alone provide.

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 dense but every sentence earns its place: scoring criteria, non-defaulting behavior, silence_hours semantics, the commodity trap, and coverage-gating behavior are all critical for correct invocation and user communication. Nothing is redundant.

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 describing both result semantics and special-case handling. It covers scoring, unscored vessels, silence_hours, the ignored commodity argument, coverage gating, and per-box coverage state, leaving little ambiguity for an agent deciding whether and how to call the tool.

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 description fully explains the commodity parameter's key quirk: it is accepted but not applied. It also gives context for min_score by describing the composite scoring model. However, limit has no schema description and the tool description does not explain its effect or default, so not every parameter is fully compensated for.

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 that the tool returns ranked shadow-fleet vessel leads and specifies the scoring basis: silence relative to each vessel's own 14-day cadence baseline, vanished-under-way status, and flag of convenience. This makes it distinct from sibling tools like query_vessels, even though no sibling is named explicitly.

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 use when shadow-fleet lead rankings are needed, and it gives operational guidance about the commodity caveat and coverage gating. However, it does not explicitly state when to prefer this tool over alternatives such as query_vessels or query_dark_contact_events, so the selection logic is left mostly to inference.

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