FEM Mesh Refinement

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

Annotations already convey readOnlyHint=false and destructiveHint=false. The description adds useful context: it is a mutation requiring an existing mesh, and the refinement only takes effect if char_length is below the global setting. It does not disclose side effects, return value, or failure modes, so 3 is appropriate.

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?

One-sentence purpose followed by a tight three-line parameter list. Every sentence earns its place and the key condition for effectiveness is included without redundancy.

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?

The description covers the prerequisite (existing mesh), semantics of all required parameters, and the units/condition for char_length. It omits the optional name parameter and some details about how refs are resolved or what the operation returns, but no output schema exists and these are secondary for invoking the tool.

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?

With 0% schema description coverage, the description carries the full burden, and it compensates well: mesh is identified as the handle, refs is described as a list of {handle, face|edge|tag} dicts, and char_length gets units (mm) and a behavioral condition relative to the global mesh. Only the optional name is left undescribed, which is minor.

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 first sentence names a concrete action ('Add') and a specific resource ('local mesh-refinement region' on an 'existing FEM mesh'). This clearly distinguishes it from general mesh operations like fem_mesh and from analysis/solver siblings.

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 states the operation is for adding a local region to an existing mesh, implying the mesh must already exist and that global refinement is not the target. The note that char_length should be smaller than the global mesh setting gives a concrete condition. It does not explicitly name sibling alternatives or exclusions, so it is not a 5.

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