add_credits

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

With no annotations provided, the description carries full burden for behavioral disclosure. While it states the tool adds credits, it doesn't describe whether this requires specific permissions, whether the operation is reversible, what happens to existing balance, or any rate limits. The testing/demo note hints at special usage context but doesn't fully explain behavioral implications.

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 extremely concise at just two sentences with zero wasted words. The first sentence states the core purpose, and the second provides important contextual qualification. Every element earns its place, and the structure is front-loaded with the primary 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?

For a financial transaction tool with no annotations and no output schema, the description provides basic purpose and usage context but lacks important details about permissions, reversibility, response format, or error conditions. The testing/demo qualification adds some context, but doesn't fully compensate for the missing behavioral transparency needed for a balance-modifying operation.

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%, so the schema already fully documents both parameters (amount_usd and agent_id). The description doesn't add any parameter-specific information beyond what's in the schema. With complete schema coverage, the baseline score of 3 is appropriate as the description doesn't compensate for any gaps.

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 action ('Add credits') and target resource ('to your account'), providing a specific verb+resource combination. It distinguishes from siblings like 'check_balance' (read-only) and 'purchase_access' (different transaction type) by focusing on balance augmentation. However, it doesn't explicitly contrast with all potential alternatives like 'setup_metered_billing'.

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 includes the parenthetical '(For testing/demo purposes)', which implies this tool should be used primarily in non-production scenarios. This provides some contextual guidance about when to use it, but doesn't offer explicit alternatives for production scenarios or clear exclusions for when not to use it.

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