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

With no annotations, the description carries the full behavioral burden. It does add genuinely useful cost and quota context ($0.01/call, one free trial per operator), but omits whether the operation is read-only, what a 'verdict' contains, what 'signed' implies about authorization, and how two snapshots are identified when the tool takes no parameters.

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 front-loaded sentence with no padding; the parenthetical cost/trial note is compact and carries real operational value. Slight cost in that the pricing aside occupies space that could have gone to the actual diff semantics.

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?

No output schema exists, so the description must explain what a verdict looks like and how snapshots are selected, and it does neither. Combined with no annotations and no parameters, an agent cannot reliably invoke this tool from the definition alone.

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 rule for zero-parameter tools is a baseline of 4, but here the description actively implies inputs ('diffing two signed snapshots') that the empty schema does not expose, leaving the agent unable to tell how the snapshots are supplied. That mismatch justifies a deduction from the baseline.

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 core action — diffing two signed snapshots to produce a verdict — is identifiable, but 'composed verdict' is undefined jargon and it is never said which two snapshots or where they come from. A reader can tell it relates to the snapshot family (take_snapshot, list_snapshots) but not precisely what output it yields.

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?

No statement of when this should be used instead of list_snapshots or take_snapshot, and no prerequisites for the 'signed snapshots' precondition. The only usage-adjacent content is a trial/pricing note, which is not selection guidance.

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