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

Annotations already declare the tool read-only and open-world. The description adds meaningful behavioral context: it checks against live current repository contents, flags mismatches like missing files or past-EOF lines, and explicitly disclaims security-bug judgment. This goes beyond the annotation baseline, though it does not describe the output format.

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?

Two tight sentences with no filler. The first sentence front-loads the core action and targets; the second sentence clarifies the tool's boundary. Every clause adds value.

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?

Given two fully documented parameters, clear scope, and read-only annotations, the description covers the essential context. The only minor gap is that it does not state the exact return format of the 'flags,' but the phrasing is sufficiently clear for an agent to infer the tool produces a list or indication of mismatched claims.

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% for both params ('repo' and 'report'), and the description does not add parameter-specific detail beyond what the schema provides. Baseline 3 is appropriate since the schema already carries the full burden for parameter semantics.

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 uses a specific verb ('Check') with a precise resource ('a vulnerability report's concrete claims... against a real public GitHub repo's current contents'). It clearly distinguishes this tool from the many other sibling checking tools by focusing on factual verification of codebase claims, not generic vulnerability assessment.

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 clearly states the tool's scope and explicitly excludes judging whether a verifiable claim is an actual security bug, saying it 'only checks whether the claim is honest about the codebase.' While it does not name alternative siblings, this boundary is enough to guide appropriate use without confusion.

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