Charlie: the trend

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

Annotations already indicate write behavior (readOnlyHint=false) and open-world effects. The description adds the context of recording a snapshot, but does not detail side effects, required permissions, or what happens to existing data. It meets a basic level of transparency given annotations.

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 concise sentence, but it lacks structured details. It could benefit from a brief parameter explanation or usage note without becoming verbose.

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 has 2 parameters and an output schema, but the description omits details about the snapshot mechanism, the meaning of 'since last time', and the output format. This leaves the agent with incomplete context for effective use.

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 has 0% description coverage. The description does not explain the 'repo' or 'online' parameters. Despite being few parameters, the description fails to add meaning beyond the schema, leaving the agent to guess their roles.

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 the tool records a toil snapshot and reports budget movement. It uses specific verbs and clearly identifies the action. However, it does not differentiate from sibling tools like charlie_did_it or charlie_summary, which could have overlapping purposes.

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 does not mention prerequisites, when not to use it, or suggest alternative tools for similar tasks.

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