json_filter

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

With no annotations provided, the description carries full burden and does well by disclosing key behaviors: automatic chunking when data exceeds 400KB (via chunkIndex parameter explanation), handling of arrays ('Arrays are automatically handled'), and the need for valid JSON shape. It doesn't mention error conditions or performance characteristics, but covers essential operational 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?

The description is appropriately sized and front-loaded with the core purpose. The shape parameter examples are extensive but necessary for understanding the tool's capabilities. The sibling tool references are efficiently integrated. Some redundancy exists between the description and schema (filePath explanation).

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 3-parameter tool with no annotations and no output schema, the description provides good coverage: clear purpose, usage guidelines, parameter semantics with examples, and behavioral transparency about chunking and array handling. It doesn't describe the output format or error responses, but given the schema coverage and behavioral details provided, it's mostly complete.

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 baseline is 3. The description adds significant value by explaining the shape parameter's purpose ('defining what fields to extract'), providing multiple concrete examples with different use cases, and clarifying array handling behavior. However, it doesn't explain the filePath parameter beyond what's in the schema.

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 specific action ('filter JSON data'), the resource ('JSON data'), and the mechanism ('using a shape object to extract only the fields you want'). It distinguishes from sibling tools by mentioning their complementary roles (json_schema for analysis, json_dry_run for size breakdown) rather than overlapping functionality.

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 explicitly states when to use this tool ('to extract only the fields you want') and provides clear alternatives: 'Use json_schema tool to analyse the JSON file schema before using this tool' and 'Use json_dry_run tool to get a size breakdown of your desired json shape before using this tool.' This gives the agent specific guidance on tool selection workflow.

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