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

No annotations are supplied, so the description carries the full behavioral burden. It discloses the validation rule (unknown names rejected with the valid list) but says nothing about whether the write merges with or replaces existing config values, what permissions are required, or what happens to fields omitted from configValues — critical gaps for a mutation tool.

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 that front-load the action and then the configValues contract, with no filler. The semicolon-chained clauses are dense but readable and every clause carries information about validation or sourcing.

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 5-required-parameter mutation tool with a nested free-form object and no output schema, the description covers the hardest part (configValues keys and their source) but omits return behavior, permissions, and the undocumented workspaceId. Without annotations to fill the mutation-safety gap, it is adequate rather than complete.

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 coverage is 60% and configValues is the weakest-documented parameter (generic object with additionalProperties: {}); the description compensates by explaining its shape as { [name]: value } and citing get_block_schema serviceConfig.fields as the authoritative source for keys. workspaceId remains undocumented in both places, but the description meaningfully upgrades the riskiest 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?

States a specific verb and resource: 'Set this workspace's config values for an extension service', with concrete examples of what a service is (Sandbox/Production environment, cluster zone). It is clearly the write counterpart to the sibling get_service_config, though it never names that sibling explicitly.

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 a concrete precondition workflow — names, types and required fields must come from get_block_schema serviceConfig.fields — and warns that any other name is rejected. It does not state exclusions or point at get_service_config for reading current values, so it stops short of full when/when-not guidance.

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