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

Annotations already declare destructiveHint=true and idempotentHint=true, so the safety bar is lower, and the description still adds real context: activation gates, the non-purchase guarantee, 402 behavior, and a secrets-handling warning. It does not say what the destructive part actually destroys (e.g., whether existing steps are replaced on update or whether pausing halts collection of existing data).

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 package prerequisite is stated twice ('never buys one' then 'never buys automatically' plus the operator-benefit variant), which wastes space in a five-sentence description. The front-loaded scope statement is good, but the middle is repetitive and the trailing Google-secrets warning is tangential to the tool's primary action.

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 4-parameter mutation with full schema coverage and existing annotations, the description covers prerequisites and the payment error path adequately. It is still missing the semantics an agent most needs: whether `steps` and `project` are replaced or merged on an existing site, and what exactly pausing or reconfiguring removes.

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 baseline is 3. The description restates the eight-step limit and the immutability of `project` (both already in the schema) and notes that Google secrets don't belong in any parameter, but adds no syntax, format, or merge-vs-replace semantics beyond the schema.

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 specific verbs and resource: enable/pause a site's collection, or set up to eight ordered project_action steps on an owned site. That is concrete enough for an agent to act. However, it never names the sibling `journeys` (presumably the read counterpart) or distinguishes itself from `list_sites`/`buy_plan`, and it drifts between 'journeys' in the name and 'collection' in the description.

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?

Gives clear prerequisites: an existing paid site package must already exist, this call never purchases one, and Google credentials are configured in the UI rather than here. It also explains the 402 path. It stops short of explicitly routing the agent to `buy_plan`/`list_plans` when no package exists, leaving that inference to the reader.

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