jev_compact

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

With no annotations, the description carries the full burden, and it explicitly discloses what is destroyed (old verbose tool results) and what is preserved (conversation messages verbatim). It stops short of saying whether the operation is reversible, how output is returned, or whether it mutates inputs, but the core safety profile is clear.

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 conveys the tool's purpose and its most important constraint. There is no filler or repetition of schema details.

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 and all three parameters have schema descriptions, so the definition is adequate for basic invocation. It does not explain what the tool returns or how rawJson and messages interact, and with no output schema those details would need to come from the description to be fully 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 coverage is 100%, so the parameters are already documented. The description adds useful context by mapping 'old verbose tool results' and 'conversation messages' to the tool's inputs, but it does not go into details about truncateHeadChars beyond 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 names a concrete operation ('prunes old verbose tool results') and a hard constraint ('preserving conversation messages 100% verbatim'), making the tool's function unmistakable. This also sets it apart from the decision/status sibling tools, which address different concerns.

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 phrase 'context compaction' implies when the tool should be used, and the preservation constraint explains a key selection criterion. It never explicitly says 'use this when context is too long' or names alternatives, so the agent must infer the usage situation.

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