Media player details

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

Annotations already declare readOnlyHint and openWorldHint=false, so the description need not restate safety. It adds real value instead: the return payload is enumerated, it discloses partial-result behavior ('codec and bitrate when they can be determined'), and it flags a dependency ('uses the full DevTools channel when available') that hints at capability-dependent results.

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, front-loaded with the substantive return-field list; nearly every clause carries information. The dense comma-separated enumeration is slightly hard to scan but nothing is wasted.

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 responsibly enumerates return fields, and the DevTools-channel note explains variability in results. The remaining gap is when-to-use versus alternative diagnostic tools, which the description leaves entirely to inference.

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 100% and all three parameters (tabId, video, sampleMs) are fully documented there, so the baseline applies. The description adds only an indirect hint that frame rate is measured, without explaining defaults, the video ref format, or the sampling window.

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?

Names a specific verb (inspect) and resource (media player) and enumerates the exact telemetry returned (resolution, dropped frames, buffered ranges, ready/network state, errors, events). It is distinguishable from video_control and video_list by being a read-only diagnostic, though it never names those siblings explicitly.

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 DevTools Media panel analogy implies the usage context (debugging playback health), but there is no explicit statement of when to prefer this over perf_metrics, perf_trace, or video_control, nor any when-not guidance. The agent must infer the routing decision.

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