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

Annotations declare readOnlyHint=true, so the safety profile is already covered; the description still adds real value by disclosing what the computation produces — per-compound draws, a combined draw with split-injection advisories, and frequency-conflict detection. With no output schema, this output disclosure matters. It omits any error/permission behavior, but none is critical for a pure calculation.

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?

A single front-loaded sentence with a colon-delimited list of three outputs, plus a short research-use trailer. Every clause earns its place and nothing is padded.

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 no output schema, the description correctly carries the return-value burden by naming the three result categories. It does not mention guidance on defaults or how the stack relates to scheduling tools like plan_schedule/get_protocol, but for a bounded calculation tool this is close to complete.

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 peptide, vial_mg, water_ml, dose_mcg, syringe_type and syringe_capacity_ml are all documented in the schema. The description adds no additional parameter meaning (e.g., how dose_mcg interacts with the draw-unit conversion), so baseline 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 ('Plan') and resource ('multi-compound stack') and enumerates the concrete outputs (per-compound draw volumes/units, combined draw volume with split-injection advisories, frequency-conflict detection). The 'multi-compound' framing implicitly separates it from single-compound calc_reconstitution, but it never names a sibling outright.

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?

Usage is only implied: the 2–4 compound scope and 'multi-compound' wording suggest this is the stack-planning tool rather than calc_reconstitution or plan_schedule, but no explicit when-to-use, when-not, or alternative is named.

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