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

Annotations already signal this is a non-read-only, non-destructive, idempotent operation, but the description adds substantial behavioral context: exact validation steps, distinct INVALID_PARAMS failures, the 'always TIGHTENS enforcement' effect, and that it applies to Lane 2. This goes well beyond the structured annotations.

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 longer than average but every sentence adds operational value: purpose, validation behavior, and side-effect semantics are all present. It is front-loaded with the main action and then details consequences, with no filler or repetition.

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 complex write operation, the description covers validations, failure modes, and the precise policy interaction, and the output schema covers return shape. It is missing only explicit usage routing and caller_id semantics, which keeps it from being fully complete.

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 0%, so the description carries the burden. It richly explains grant_pda (base58 32-byte address, on-chain DelegationGrant, not revoked/expired, delegate match) and wallet_address (the wallet being opted in). However, caller_id is not described at all, leaving one parameter semantically undocumented.

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: 'Opt a wallet into an AGNTA DelegationGrant spend/scope cap.' It clearly distinguishes this from siblings like clear_agnta_grant and set_wallet_policy by explaining it adds an additional, non-replacing cap.

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 implies when to use the tool — when you want to enforce an additional DelegationGrant cap without replacing WalletPolicy — but it never explicitly names alternatives or states when not to use it. The distinction from set_wallet_policy is implied through 'never replacing', not stated as a routing rule.

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