h_add

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

Annotations already declare destructiveHint=true, idempotentHint=true and readOnlyHint=false, so the mutation profile is covered; the description adds no context beyond that, such as that atom counts and coordinates change, that existing hydrogens are retained or replaced, or that failures can occur on residues lacking templates. "Adds" is at least consistent with destructiveHint, so there is no contradiction.

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?

It is a single short sentence with zero redundancy and is front-loaded, which is good. However, this brevity is under-specification rather than economy: the one line is all the guidance the agent gets for a destructive structural mutation.

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?

An output schema exists, so return values need not be explained, but for a destructive structure-modifying tool with a highly ambiguous sibling (h_fill) the description is too thin. It omits how the selection is interpreted and how this differs from the other hydrogen-handling tools, which is exactly what an agent needs before invoking it.

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 a single optional parameter defaulting to "all" and described as "Where to add hydrogens." The description's phrase "to a selection" mirrors the schema rather than extending it — no selection syntax, scoping, or default behavior is elaborated. Baseline 3 applies when the schema carries the parameter documentation.

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 states a verb and resource ("Adds hydrogens") plus a target ("a selection"), but since the tool name is already h_add, it adds little beyond the name. It never clarifies what a "selection" is in this environment (PyMOL selection expression, object, or the literal default "all"), leaving the actual scope of the operation ambiguous.

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?

There is no when-to-use guidance at all: nothing distinguishes h_add from the sibling h_fill, which also adds hydrogens, or from rebuild/bond/remove, and no prerequisites (protonation state, pH, missing templates) are mentioned. An agent cannot tell from the text which hydrogen-adding tool is correct for a given situation.

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