index_stats

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

No annotations are provided, so the description carries the burden. It discloses that the tool reads from moviola.db and returns aggregate metrics, implying a read-only stats operation, but it does not explicitly state read-only behavior, permissions, missing-database behavior, or how db_path affects the source.

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 wasted words. The resource, source, and returned metrics are all stated compactly.

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?

For a low-complexity stats tool with no output schema, the description adequately identifies the returned metrics. However, it omits parameter behavior and usage guidance, leaving clear gaps for an agent deciding how to call it.

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 sole parameter db_path has 0% schema description coverage and is never mentioned in the description. The phrase 'from moviola.db' hints at a default database but does not explain that db_path can override it or what happens when it is null.

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 resource ('per-preset totals') and concrete metrics (counts, bytes in/out, mean ratio), making the tool's function clear. It does not explicitly distinguish itself from siblings like list_presets or index_history, so it falls short of a 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 guidance on when to use this tool versus alternatives such as list_presets or index_history. The agent must infer its role from the phrase 'per-preset totals' alone.

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