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

Annotations already declare the mutation profile (readOnlyHint=false, idempotentHint=true, destructiveHint=false), but the description goes well beyond them: it discloses replacement semantics ('Replaces guidelines the workspace has'), a validation step ('SnapHost checks that it answers with a page or a PDF'), and persistence ('every build in the workspace reads it from then on'). Permission/plan gating is spelled out as well.

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?

It is a single dense paragraph, but it is front-loaded with the core action and every clause carries information (validation, persistence, replacement, permissions, alternative path). Minor cost: the parenthetical enumerations and stacked conditions make it harder to scan than a bulleted form.

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 write tool with full annotation coverage and no output schema, nothing an agent needs is missing: prerequisites, replacement behavior, validation, persistence via get_brand_kit, and the out-of-scope fallback are all stated. Return values need not be described since no output schema exists.

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, and the schema already defines both the url and workspace_id semantics. The description still adds real meaning about what the url must point to (a page/PDF constraining logo clear space, imagery, chart drawing, brand voice) and the constraint that offline PDFs are out of scope for this parameter.

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 states a precise verb and resource ('Link the active workspace's brand guidelines') and pins down exactly what the resource is ('the https URL of a public web page or PDF that says what the kit cannot hold'). It also names the read-side sibling (get_brand_kit), so an agent understands where the linked value surfaces. The only unaddressed relative is set_brand_kit, but the operation itself is unambiguous.

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?

It gives explicit preconditions (workspace owner only, on Pro, in a team workspace, including the otherwise-fixed website workspace) and an explicit alternative path for the case it does not cover ('a PDF that is not online is uploaded on the General page of the dashboard instead'). It even adds a procedural guardrail: 'Confirm the link with the person before calling this.'

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