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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety/purity profile is covered. The description adds that it returns amendment type and kg/m², which is real behavioral context, but says nothing about the formula, edge cases when pH already equals target, or limits.

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 computation, then usage context, inputs, and return value in a compact block. The trailing 'See list_bundles...' sentence is loosely relevant and slightly off-topic for this specific calculator, but overall it is efficient.

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?

A pure, read-only calculation with an output schema, so return-value detail is not the description's burden. It covers purpose, inputs, and output shape adequately; only the routing distinction from similar pH/soil calculators is under-developed.

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 fully documents current_ph, target_ph, and area_m2 (including min/max bounds). The description merely restates the three inputs and adds no format, unit, or range nuance beyond the schema, so baseline 3 is appropriate.

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+resource: 'Compute lime or sulfur amount to shift soil pH to a target.' An agent can tell what it produces. However, it never differentiates from near siblings like calculate_ph, calculate_garden_soil, or calculate_raised_bed_soil, instead pointing to list_bundles for related calculators.

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 gardening' implies the domain but gives no explicit when/when-not guidance and no named alternative among the ~300 calculate_* siblings. The pointer to list_bundles is a discovery aid, not a usage rule for choosing this tool over others.

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