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

Beyond the annotations (readOnlyHint, idempotentHint, openWorldHint=false), the description adds the operational envelope an agent needs: no side effects, no network, no stored state, determinism, and hard limits of 64 KB input, 1 s per call and 1 MB result. These limits and the determinism guarantee are not obtainable from the annotations and directly affect whether the tool is safe to call on large payloads.

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?

The label-segmented structure (Cuándo / No para / Efectos secundarios / Determinista / Límites) is strongly front-loaded and each segment earns its place. The appended partial English restatement, which trails off into a pointer to inputSchema.description, is redundant filler that dilutes the otherwise tight framing.

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 six parameters including a nested pairs array, rich annotations and a dedicated output schema, the description covers everything the schema cannot: cost limits, determinism, absence of side effects, and the distinction from json-pointer-get. Return-value detail is correctly left to the output schema.

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 parameter baseline is 3. The description recaps the salient behaviors (optional default, case- and accent-insensitive matching, trimming, reporting whether the key was found and which table key matched) but adds no syntax, precedence or edge-case detail beyond the schema, e.g. what happens when both table and pairs 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?

The description names a specific verb+resource (mapping a key to a value through a lookup table) and enumerates the two supported table shapes (object or list of key/value pairs). It explicitly rules out a sibling by name, json-pointer-get, so an agent can route correctly without opening a schema.

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?

It has an explicit 'Cuándo' clause (exact transform/compare/check of structured data such as JSON, CSV, YAML, XML, arrays) and an explicit 'No para' clause that names the alternative tool json-pointer-get and the scenario it serves. Both the positive trigger and the exclusion are present.

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