femm_add_block_label

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

With no annotations, the description carries the full burden and does well: it discloses the magnetics-only scope of circuit/magdir/turns, that negative turns means opposite direction, that mesh_size None means automatic, and that a wrong-region label is a common bug. It does not cover error behavior or the session parameter, but the behavioral surface is largely disclosed.

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 lead sentence states the action and scope immediately, followed by a parameter glossary and a caveat sentence. Dense but front-loaded and each line carries information; only the slightly ragged line-wrapping keeps it from being maximally clean.

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 9-parameter mutation tool with no annotations and no output schema, the description supplies purpose, prerequisites, parameter semantics, and a placement pitfall. It omits the session parameter and any return/error behavior, leaving a small but real 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?

Schema description coverage is 0%, so the description must compensate and it does for material, mesh_size, circuit, magdir, turns, and group, explaining defaults and semantics (e.g., '' for no circuit, integer group for selection/integrals). x/y and session are left unexplained, but x/y are self-evident coordinates, so the compensation is strong overall.

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?

States a specific verb+resource ('Add a block label') plus the coordinates and the 'in one call' property assignment. It is clearly distinguishable from sibling mutation tools like femm_set_block_prop (which modifies an existing label) because it is an additive creation tool.

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?

Provides context on dependencies: material must come from femm_material_load/femm_material_add or be '<No Mesh>' for a hole, circuit names come from femm_add_circuit, and it recommends checking placement with femm_geometry_summary. It gives clear preconditions but does not explicitly state when to prefer this over femm_set_block_prop.

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