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

Annotations already declare this is a write (readOnlyHint=false) that is non-destructive and closed-world. The description adds two useful facts beyond that: the output is a NEW record (consistent with destructiveHint=false) and only the first product is emitted for downstream nodes. It does not explain ambiguity handling, whether inputs are consumed, or how the enumerated constructs relate to the single emitted product.

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?

Two compact sentences with the verb and method front-loaded and no filler. Slightly terse given a 12-parameter tool, but nothing is wasted.

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, and the schema documents all 12 parameters including the nested _subject/_files shapes. Still, for a complex assembly tool the description is thin: it never mentions the multi-construct enumeration (max_constructs, topology) that coexists with the 'first product' emission, and gives no guidance on how fragments must be prepared.

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 100% and the schema itself is unusually rich (exclusive max_homology_bp bound, DnaCauldron gate scale for min/max_tm, fragment wiring notes). The description contributes nothing parameter-specific, so the baseline 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?

States a specific verb and resource — 'Assemble fragments by terminal homology' — and names the concrete methods (Gibson / NEBuilder / In-Fusion, DnaCauldron), which implicitly separates it from golden_gate_assemble and ligate_fragments. It stops short of naming siblings explicitly, so an agent must still infer the boundary.

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 statement of when to choose this over golden_gate_assemble, recombine, fusion_pcr, or restriction_ligate, and no prerequisites (e.g. that fragments must already carry matching terminal homology arms, or that design_gibson_primers precedes it). Only the method list hints at the appropriate scenario.

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