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

Annotations already declare readOnlyHint=true, destructiveHint=false, openWorldHint=false, so safety is covered; the description adds genuinely new operational context — that files in protected folders (Downloads, Desktop, Documents) require Full Disk Access for LMCP. It also implies the return payload by naming the fields. No pagination/latency/error detail, so not a 5.

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?

Three tight sentences: what is returned first, then when to use it, then the permission caveat. Every sentence carries distinct information and the payload comes before the edge-case note.

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 no output schema, the description compensates by enumerating the returned fields, so an agent knows what it gets back, plus the usage context and the Full Disk Access constraint. Nothing material is missing for a single-parameter read-only probe.

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?

Only one parameter (path) with 100% schema description coverage, so the schema baseline applies. The description adds marginal value by noting the path may live in protected folders requiring elevated access, which is a real invocation consideration rather than a restatement.

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?

States a specific verb (Reports) plus the exact resource and enumerates the returned fields: duration_ms, width, height, fps, audio presence, file size. This clearly separates it from editing siblings like video_trim or video_reframe, which consume this data rather than produce it.

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?

Explicitly says to call it 'before editing to reason about the footage' and names two concrete downstream workflows (compute trim ranges, pick a reframe crop), which effectively routes the agent to video_trim/video_reframe after probing. No explicit when-not or prerequisites beyond the permission caveat.

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