function_completions

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It mentions 'using orderless' but does not explain what this entails (e.g., case sensitivity, matching behavior, or performance implications). It also omits details like return format, pagination, or error handling, which are critical for a tool with no output schema. This results in significant gaps in 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 a single, efficient sentence: 'Return all function names matching a prefix using orderless.' It is front-loaded with the core action and resource, with no wasted words. Every part of the sentence contributes directly to understanding the tool's purpose, making it highly concise and well-structured.

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 tool's complexity (a search/retrieval operation with no output schema and no annotations), the description is incomplete. It fails to address key aspects such as the return format, how 'orderless' affects matching, or potential limitations. Without this information, the agent lacks sufficient context to use the tool effectively, especially in comparison to siblings like 'variable_completions'.

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?

The schema description coverage is 100%, with the parameter 'function_prefix' documented as 'Prefix to match.' The description adds minimal value beyond this, only restating 'matching a prefix' without providing additional context like examples or constraints. Given the high schema coverage, the baseline score of 3 is appropriate, as the description does not compensate with extra semantic details.

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's purpose: 'Return all function names matching a prefix using orderless.' It specifies the verb ('Return'), resource ('function names'), and key constraint ('matching a prefix'), which is specific and actionable. However, it does not explicitly differentiate from sibling tools like 'function_documentation' or 'variable_completions', which reduces it from a perfect score.

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 provides no guidance on when to use this tool versus alternatives. It lacks context about scenarios where this is appropriate, prerequisites, or comparisons to siblings such as 'variable_completions' or 'command_completions'. This absence of usage instructions leaves the agent without direction for selection.

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