h_add

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

No annotations are provided, and the description only states the action itself. It does not disclose side effects, whether existing hydrogens are replaced, or any state changes, leaving behavioral characteristics largely hidden.

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 a single, focused sentence with no redundancy. It is highly concise and front-loaded, putting the action and target first.

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 simple one-parameter interface and presence of an output schema, the description is minimally sufficient. However, it lacks usage context, alternative tool differentiation, and behavioral disclosures, creating a slight gap.

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?

The schema fully documents the selection parameter with its default 'all' and description 'Where to add hydrogens.' The tool description adds nothing beyond the schema, so the baseline score of 3 applies.

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 uses a specific verb ('Adds') and resource ('hydrogens') plus target ('to a selection'), clearly conveying the operation. It doesn't distinguish from the sibling h_fill, but the core purpose is unambiguous.

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?

No guidance is given about when to use h_add versus alternatives like h_fill, or any context about preparation steps or prerequisites. The description simply states the action without usage scenarios.

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