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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=true, so safety is covered by structured data. The description adds genuine value by disclosing the single-value scope and the simple-path/array-index syntax, but it says nothing about behavior on a missing path or malformed JSON.

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 an inline example, no filler, and the key limitation ('one value') placed before the syntax details.

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 two-parameter, read-only tool with no output schema, the description is close to sufficient, but it omits the failure contract (error vs null on a non-existent path) and any note on return typing, which an agent needs to interpret results.

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% and both parameters are documented with their own examples, including the 100 KB size limit on 'json'. The description's path example duplicates the schema, so it adds no semantics beyond structured data; 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?

The description states a specific verb (Extract) and resource (a value from JSON) with a concrete example path, so the core function is unambiguous. It does not, however, position itself against the adjacent json_validate or csv_to_json siblings, so the agent must infer the boundary.

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 implied by the constraint 'one value' and 'simple dot path', which hints at when this is the right tool versus a fuller query language, but there is no explicit when-to-use or when-not-to-use guidance, and no sibling is named as an alternative.

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