Gemini Extract Tool

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

The readOnlyHint annotation already establishes this is a safe read operation, so the safety profile is covered. Beyond that the description discloses nothing: no mention of model selection impact, cost/latency, or what 'structured data' actually comprises. For a tool with a configurable model and extraction type, more context was expected.

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 zero filler. It is well-formed and wastes nothing, though its brevity leaves it thin for a 4-parameter tool.

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?

An output schema exists so return values need not be explained, but key semantics remain uncovered: what 'custom' extract_type means, when custom_fields applies, and how this differs from the sibling extraction tools. For a moderately parameterized tool the description is too sparse.

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 schema already documents text, model, extract_type, and custom_fields. The description adds no syntax or usage meaning beyond that, so the baseline 3 applies.

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?

States a clear verb ('Extract') and resource ('structured data from text'), so an agent knows the general operation. However, it offers no differentiation from close siblings such as gemini_structured_tool, gemini_extract_tables_tool, or gemini_extract_from_url_tool, leaving the agent to guess which extraction variant to pick.

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?

There is no when-to-use guidance, no mention of when not to use it, and no reference to any alternative tool. The agent gets no signal about how this differs from the many other extraction/structured siblings.

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