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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so credit goes to the added algorithmic context: the exact formula and the note that it returns the missing value plus an acidity class. It stops short of return format or edge-case handling (e.g. zero/negative concentration).

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-loaded with the core action and formula in the first two sentences, then inputs and return behavior; every sentence is short and useful. The inputs line mildly duplicates the schema, but there is no filler.

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 annotations, full schema coverage, and an output schema in place, the definition supplies what remains: purpose, formula, accepted inputs, and expected output. Only minor gaps (what happens if both inputs are given, valid pH ranges) keep it from fully 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% with only two parameters, so the schema already documents pH and H+ mol/L; the description merely restates them including the same mol/L unit. Baseline 3 is appropriate since it adds no new semantics such as valid ranges or which argument wins if both are supplied.

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 ('Compute pH from H+ concentration or vice versa') and makes the bidirectional behavior explicit with the actual formula pH=-log10[H+], which cleanly separates it from neighbors like calculate_soil_ph_amendment or calculate_pool_chlorine.

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?

'Use for chemistry or aquarium care' gives loose domain context but never states when to prefer this over a sibling such as calculate_soil_ph_amendment, and there are no exclusions or prerequisites. Usage is implied rather than routed.

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