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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds substantive context beyond that: every verdict reports what broke, where, and the remedy, and a false verdict is meant to halt the downstream chain. It does not discuss cost, limits, or failure modes of the check itself.

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 sentences, front-loaded with the verdict definition and closed with the actionable gating rule. No filler; the enumerated checks double as scope statement.

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?

With an output schema present, return-value explanation is unnecessary, and the description covers the core checks plus the operational role in a workflow. It leaves the advanced/degenerate parameter cases (cai_organism pairing, gc_window locality, sequence defaulting to the open record) entirely to the schema, which is acceptable given 100% coverage but slightly thins the picture for a 16-parameter 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?

Schema description coverage is 100%, so the schema already documents all 16 parameters including units, ranges, defaults, and 'Advanced' markers. The description recaps the constraint categories (length/GC/CAI bounds, forbidden sites, protein preservation) but adds no syntax or format detail beyond the schema. Baseline 3 is correct.

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 specific verb ('decide whether...') and resource (a sequence's scientific admissibility) and enumerates the exact invariants checked — protein identity, forbidden sites, reading frame, length/GC/CAI bounds. That enumeration effectively separates it from general validation siblings, though no sibling tool is named explicitly, so it stops short of a 5.

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?

Gives explicit workflow placement: 'Run this after any design or optimisation step, and stop the chain when `admissible` is false — never report a designed sequence without it.' That is clear when-to-use guidance with a gating rule. It does not name alternative checkers (e.g., verify_construct, check_manufacturability) or state when this is not the right tool, so it misses the exclusion half of a 5.

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