video_cost_ledger

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

With no annotations provided, the description carries the full burden, and it does convey that this is a read-only aggregation over "known" events (implying it only reflects already-recorded costs, not projected ones). It does not state permissions, whether it mutates anything, or what happens when no events exist, so it is only partially transparent.

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 no filler or redundancy. It is efficient, though arguably so terse that it omits context an agent would need.

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 described, and the tool has only one trivial string parameter. Still, with no annotations and no usage guidance, the definition leaves the agent without enough to confidently decide when this tool applies versus estimate-oriented siblings.

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 0% and the single required parameter (project_dir) is undocumented in the schema. The phrase "for the project" loosely signals that the parameter identifies a project, but gives no hint about format, path expectations, or whether the directory must already exist.

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 specific verb ("Sum"), a specific resource (USD cost events), and a grouping scope ("by category for the project"), which is enough to distinguish it from rendering/editing siblings like video_estimate_operation. It stops short of explicitly contrasting itself with any sibling, so it lands at 4 rather than 5.

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 statement of when to reach for this tool, what prerequisite state it needs (e.g., a project with recorded cost events), or which alternatives to prefer when only estimates rather than actuals are wanted. Usage is left entirely to inference.

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