rb209_soil_nutrient_index_by_index

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

Annotations are absent, so the description carries the full burden of behavioral disclosure. It reveals only that this is a GET (read-only) returning a single item; it does not disclose valid value domains for nutrientId or indexId (RB209 indices are a bounded scale), error/not-found behavior, or response shape. Beyond the HTTP method embedded in the endpoint, an agent learns almost nothing about runtime behavior.

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?

One compact sentence with the endpoint front-loaded followed by the scoping clause; there is no filler. The endpoint path redundantly restates parameter names already in the schema, which is mildly redundant but does not detract from readability.

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?

For a simple two-parameter read endpoint with full schema coverage, the description is nearly viable: an agent can identify the resource and the required keys. However, with no annotations and no output schema, the description leaves the response format, the valid ID value domains, and sibling disambiguation (notably rb209_soil_nutrient_index_id_from_value and rb209_soil_nutrient_indices) unstated.

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% — both parameters have descriptions ('The index id to filter on', 'The nutrient id to filter on') — so the baseline is 3. The description's phrase 'filtered by nutrient id and index id' merely restates the schema; it adds no new meaning about valid ranges or domain semantics (e.g., which nutrientId values map to N/P/K).

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 resource ('Individual nutrient index item') and the two filter keys (nutrient id, index id), with the GET verb implied by the endpoint. The word 'Individual' distinguishes it from the plural list siblings like rb209_soil_nutrient_indices and rb209_soil_nutrient_indexes. However, it does not explicitly disambiguate from rb209_soil_nutrient_index_id_from_value, which also returns a single index item via a different lookup path.

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 when-to-use guidance is provided. The description implies the call pattern ('filtered by nutrient id and index id') but never states when this endpoint should be preferred over lookalike siblings such as rb209_soil_nutrient_index_id_from_value or rb209_soil_nutrient_target_index. Given the large sibling group, an agent has no basis for choosing between the alternative single-item lookup tools.

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