create_finger_joint

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

No annotations are present, so the description carries the full burden, and it does well: it states units, that defaults are tuned for ~100 mm boards, and critically discloses failure behavior (non-zero 'failed' means cuts didn't apply, likely non-manifold geometry) plus a verification path via bbox_mm. It omits mutation side-effects such as whether the boards are modified in place or reversibility.

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?

Front-loads the purpose, then constraints, then return shape in three compact blocks with no filler. Slightly dense in the returns sentence, but every clause carries information.

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 geometry mutation with no annotations, the description covers units, preconditions, default sizing, and failure interpretation. An output schema exists so return details were not strictly required, yet the explicit failure guidance is a genuine addition; only mutation side-effects remain unstated.

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%, so the baseline is 3, but the description adds cross-parameter meaning the schema lacks: offsets are measured from the board face's center, all values are in mm, and the default set is sized for ~100 mm boards. That is real interpretive value beyond the per-field schema text.

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 and resource ('Create a finger joint (box joint) between two boards') and even supplies the synonym 'box joint'. It does not explicitly contrast itself with siblings like create_mortise_tenon or create_dovetail, but the joint type is definitionally distinct so an agent can still select it.

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 a concrete applicability precondition: 'The two boards must already touch/overlap along the joint axis.' That tells the agent when the call is valid. It does not, however, name alternatives (mortise-tenon, dovetail) or state when-not-to-use, so it falls short of a 5.

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