field_caps

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

No annotations are provided, so the description carries full burden for behavioral disclosure. It mentions '返回字段在各索引中的类型和能力' (Returns field types and capabilities across indices), which gives some output context, but doesn't describe whether this is a read-only operation, what permissions are required, whether it's resource-intensive, or how results are structured. For a tool with zero annotation coverage, this is insufficient behavioral transparency.

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 concise with three brief lines: purpose statement, parameter list, and return information. It's front-loaded with the main purpose. While efficient, the Chinese formatting with line breaks is slightly less structured than ideal but remains readable.

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?

Given the complexity of Elasticsearch operations, zero annotation coverage, no output schema, and 0% schema description coverage, the description is incomplete. It doesn't explain what 'field capabilities' include, how results are formatted, whether this is a metadata query versus data query, or any error conditions. For a tool in this ecosystem with many alternatives, more context is needed.

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 0%, so the schema provides no parameter documentation. The description lists parameters 'index' and 'fields' with minimal explanation ('索引名称' for index, '字段列表' for fields). This adds basic meaning but doesn't explain what format fields should be in, whether wildcards are allowed, or what happens with multiple indices. The description compensates somewhat but not fully for the schema gap.

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 '获取字段能力信息' (Get field capability information), which provides a basic purpose but lacks specificity about what 'field capability' means in this context. It doesn't distinguish this tool from other field-related tools like 'cat_fielddata' or 'index_get_mapping' among the many siblings. The purpose is vague rather than clearly differentiated.

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 guidance is provided about when to use this tool versus alternatives. With many sibling tools related to indices, fields, and data operations, there's no indication of when field_caps is appropriate compared to tools like 'index_get_mapping', 'cat_fielddata', or 'search'. The description offers no context about use cases or exclusions.

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