Media Source Inspect

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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the bar is lower, yet the description adds genuinely useful behavior beyond them: this call performs no network contact and no download, i.e. it is a pure local syntax/capability check. It does not describe the return format, but an output schema is present.

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?

One sentence, front-loaded with the verb and resource, with the distinguishing constraint appended. No filler whatsoever.

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?

Complete enough to call correctly: the parameter is fully documented in the schema, the return contract is covered by the output schema, and annotations supply the safety profile. The only residual gap is a slightly clearer statement of when to prefer this over media_info or media_acquire.

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?

There is a single parameter at 100% schema description coverage ('Local video path, YouTube/Loom URL, or HTTPS direct video/HLS URL'), so the schema fully documents accepted input forms. The description adds nothing parameter-specific. Baseline 3 is appropriate when the schema does all the work.

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+resource: 'Inspect source syntax and capabilities.' The qualifying phrase 'without contacting or downloading it' implicitly carves out territory from siblings like media_info, media_acquire, and source_ingest, so an agent can distinguish this as a dry validation step. It stops short of a 5 because no sibling is ever named.

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 'without contacting or downloading' clause implies the right moment to call it (pre-flight validation before acquisition/ingest), but the description never states that usage explicitly and names no alternatives. Usage must be inferred from the negative qualifier rather than read directly.

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