invariance_case_create

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

Annotations already communicate readOnlyHint=false and destructiveHint=false, so it is known this is a mutating but non-destructive operation. The description adds useful behavior beyond the annotations by stating that a new case is created, that it has many related runs across time/agents/humans, and that the function returns the case so its id can be reused with invariance_run_start. It does not go into idempotency or whether duplicate cases are possible, but core behavior is clear.

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 sentences accomplish a lot: defining the resource, giving the conceptual lifecycle, and stating the return value and next-step workflow with invariance_run_start. No filler is present, and the key actionable information is front-loaded.

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?

Given the 7-parameter schema with full descriptions and annotations covering mutation safety, the description is complete enough. It covers the creation outcome, the return value, and how the returned id feeds into the next natural step. A small inclusion like when to use a different case-creator would make it more complete, but the current description is sufficient for correct invocation.

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 input schema already has 100% description coverage for all 7 parameters, so the baseline is 3. The description does not need to repeat parameter details, and the small hints it gives (e.g., a case is aligned with a workflow instance) reinforce the meaning of workflow_key without adding explicit parameter-level guidance 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?

The description states a specific verb and resource ('Create a workflow-instance Case') and clarifies what a case is conceptually ('owns many runs across time, agents, and humans'). It distinguishes this from other case-type tools in the sibling list by emphasizing workflow instances, and it mentions using the returned id with invariance_run_start, making the purpose unmistakable.

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 provides clear context for when to create a case: a case is a logical grouping for runs, and the returned id should be used to link subsequent runs. It does not explicitly name alternatives or exclusions (e.g., 'use invariance_eval_case_create for eval cases'), but the 'workflow-instance' framing and run-starting linkage give a strong implicit usage boundary.

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