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

Annotations declare destructiveHint=true, readOnlyHint=false, idempotentHint=false, and openWorldHint=true, and the description is consistent with them rather than contradicting them: it explains the merge-only-adds semantics and that forceFresh is the sole way to discard prior findings. However, it adds little beyond what the schema property descriptions already disclose about these behavioral traits, and it never addresses auth/permission requirements or failure/retry behavior on repeated scans.

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?

Front-loaded with the core action and a numbered "Two uses:" structure, so an agent can scan it quickly. It is on the verbose side and duplicates much of the schema text, but the redundancy reinforces the merge-vs-replace rule rather than padding.

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?

For a mutating, non-idempotent tool with no output schema, the description covers when it applies, the side effects (merge vs forceFresh discard), and the important non-effect (approved brand guide unchanged). Combined with the annotations and full schema coverage, an agent has everything needed to call it correctly.

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% and the parameter docs are already rich and near-identical to the description's wording (e.g. the websiteUrl correction/omission semantics and the forceFresh "merging only ever adds" note are duplicated almost verbatim). The description adds the framing of the two modes but no syntax or edge-case detail the schema lacks, so baseline 3 is appropriate.

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+resource ("Re-runs the website scan") and immediately enumerates the two distinct use cases (recovery after failure, refresh/correct an active brand). This clearly separates it from siblings like create_brand, generate_brand_guide, and regenerate_brand_guide_section, which an agent could otherwise confuse with a rescan.

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?

Explicitly names when to use each mode with preconditions (brand status="failed" vs "active"), when to pass websiteUrl versus omit it, and draws an explicit boundary — "this does NOT by itself update an already-approved brand guide (call generate_brand_guide again for that)". No inference required to pick the right tool or the right path.

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