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 agent knows this is a safe, non-mutating operation. The description adds clarity that it uses dot-notation and supports array index access. No contradictions with annotations. Could mention what happens when the path is not found (undefined/null) or if input is invalid, but annotations reduce the burden.

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?

Two sentences, zero waste. Front-loaded with core purpose and examples. Every word earns its place. A model of conciseness.

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?

The tool is simple (2 params, both required), has full schema coverage, comprehensive annotations, and an output schema. The description adequately covers the core behavior and path syntax. Could briefly mention return type (any) or error case behavior, but with output schema present and low complexity, this is sufficient.

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 both 'path' and 'input' parameters well-documented in the schema. The description reinforces the dot-notation format and gives examples, but adds no semantics beyond what the schema provides. Baseline 3 is appropriate given full schema coverage.

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 clearly states the tool extracts a value from a JSON string using dot-notation path, with concrete examples like 'user.address.city' and 'items.0.name'. It also notes array index access via numeric path segments. This is a specific verb+resource pairing that distinguishes it from sibling tools like 'flatten_json', 'transform_json_array', 'json_to_csv', or 'json_schema_validate'.

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?

The description implies usage (reading values from JSON) but provides no explicit guidance on when to use this tool versus alternatives like 'extract_json_from_text', 'json_diff', or 'json_schema_validate'. No when-not-to-use conditions or alternative tool mentions. Minimal but functionally adequate.

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