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

With no annotations provided, the description carries the full burden of behavioral disclosure. It thoroughly explains the one-time SPL approve transaction, capped revocable allowance, that funds remain in the user's balance, and the revocation capability. This goes well beyond typical descriptions and helps an agent understand side effects and safety properties.

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?

The description is dense but not overly long. It front-loads the main purpose and packs in critical details like transaction type, security properties, and alternatives. While it is a bit verbose, every sentence adds value and there is no wasted content.

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 tool's security-sensitive nature and lack of output schema, the description is remarkably complete. It covers what the tool does, what it returns (a one-time approve tx), safety limits, fee-payer scenarios, and alternatives for humans. This is sufficient for an agent to select and invoke the tool correctly.

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% with both parameters described. The description adds meaningful context beyond the schema, especially for cap_usdc: 'e.g. 5 = 100 entries at $0.05' and 'Hard-capped for safety.' This clarifies the practical meaning and safety intent, going beyond the schema's basic description.

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 the tool's purpose: 'Enroll in the Entry Vault so the engine can enter you into contests with NO per-entry signing.' It uses a specific verb+resource combination and explicitly distinguishes from siblings like revoke_entry_vault and start_onboarding by mentioning them as alternatives.

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?

It provides explicit guidance on when to use this tool (to allow unattended contest entries) and gives alternatives: 'Revoke anytime with revoke_entry_vault' and mention that start_onboarding handles enrollment for humans. It also clarifies the fee-payer scenario where no SOL is needed.

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