Context pack statistics

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

No annotations are provided, so the description bears full responsibility. It indicates a non-destructive read ('estimate token cost') but fails to disclose return format, side effects, or auth needs. The added context is minimal beyond the schema.

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?

Two sentences efficiently convey purpose and usage guidance. Front-loaded: first sentence states the core action, second adds context. No unnecessary words.

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?

With 3 undocumented parameters and no output schema or annotations, the description is insufficient. It does not clarify parameter effects, return value, or tie to sibling tools beyond implied differentiation. More detail is needed for an agent to invoke correctly.

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 0% with no parameter descriptions. The description offers no explanation of 'compact,' 'diff,' or 'root,' leaving agents to guess their meaning. It fails to compensate for the schema's lack of documentation.

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 estimates token cost of a context pack, without returning full markdown. It distinguishes itself from siblings: pack_context likely returns full markdown, session_brief provides a session summary. The verb 'estimate' specifies the operation type.

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 suggests usefulness for before/after comparisons, indicating when to use. It implicitly differentiates from pack_context by noting it does not return full markdown. However, it lacks explicit exclusions or alternative suggestions beyond the sibling context.

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