CloudKit: Diff Schema

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

Annotations already declare readOnlyHint=true, and the description reinforces this by saying it only shows what would change. It adds important behavioral context beyond the annotation: production is additive-only and irreversible, fields can be added but never removed/renamed/retyped, and a non-additive diff is a stop signal. This is valuable interpretive guidance for the agent.

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?

Three sentences, each earning its place: first states the core purpose, second gives workflow placement, third warns about production irreversibility. The most important scoping information is front-loaded, and there is no redundant filler.

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 read-only diff tool with one optional parameter and no output schema, the description adequately explains the return shape ('one row per change') and the critical production constraints needed to interpret results. It could detail the exact fields present in each diff row, but the description provides enough context for correct invocation and basic interpretation.

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?

The description does not elaborate on the containerId parameter, but schema description coverage is 100% and the parameter already has a clear description with an example and fallback via CLOUDKIT_CONTAINER_ID. The baseline 3 applies because the schema carries the semantic weight and the description adds no extra parameter meaning.

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 opens with a specific verb and resource: 'Show what deploying would change: the pending differences between the container's DEVELOPMENT and PRODUCTION schemas, one row per change.' This states exactly what the tool does and its output granularity. It also distinguishes itself from schema validation and export siblings by framing the output as a deploy-impact diff.

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 gives explicit sequencing guidance: 'Read this before cloudkit_deploy_schema.' This tells the agent when in a workflow the tool is valuable. It does not explicitly name alternatives or when not to use it, but the pre-deploy context is a clear usage signal.

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