vc_idempotency_guard

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

Discloses that it is advisory-only with no local writes, describes authentication requirements (X-Vibes-Key or x402), and states return type (JSON assessing key presence/durability or payment_required). No contradiction with annotations (readOnlyHint, idempotentHint, destructiveHint).

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?

Concise at 6 sentences, front-loaded with purpose, no redundant information, each sentence serves a clear function.

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 4 parameters (1 required), 100% schema coverage, and an output schema, the description covers purpose, usage, auth, behavior, and return format fully, leaving no significant gaps.

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%, but the description adds meaning by linking the payment_signature parameter to x402 authentication, and explicitly mentions the required idempotency_key, providing context 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?

Clearly states the tool checks idempotency protection for paid actions, uses specific verb 'check' and resource 'paid action protected by idempotency key', and distinguishes from siblings vc_agent_state_guard and vc_retry_storm_guard.

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?

Provides explicit when-to-use ('before retrying a payment or other side-effecting call') and when-not-to-use ('Do not use for content fetch — use vc_web_search / vc_page_markdown'), and names alternatives.

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