Save Checkpoint

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

The description says 'Runs in background — returns immediately,' adding behavioral context beyond annotations. However, the idempotentHint: true annotation conflicts with the verb 'Create,' which typically implies non-idempotent behavior. The description does not clarify idempotency, creating a contradiction.

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 concise sentences: first defines core action, second gives critical usage warning. No redundancy, 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?

Covers main behavior (background) and capacity handling. Lacks mention of return value or success/error indications, but no output schema is present. Reasonably complete given sibling context.

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 100%, but the description adds context: 'named checkpoint' hints at the 'name' parameter, and the full-slots warning relates to 'max_checkpoints.' No additional details on 'description' parameter are given.

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 clearly states 'Create a named checkpoint of the entire project,' specifying verb and resource. It differentiates from sibling tools like vigil_delete, vigil_diff, vigil_list, and vigil_restore by focusing on creation.

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?

Explicitly instructs the agent: if slots are full, DO NOT auto-retry but ask the user to delete or increase capacity. This provides clear when-not-to-use and alternative actions, though does not compare to siblings directly.

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