Video Frame By Query

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

Goes well beyond the annotations by disclosing tie-breaking ("ties choose the earliest segment"), the timebase ("container-relative presentation clock"), abstention semantics, the unverified nature of the supplied transcript, and that the frame carries measured PTS. This is substantive operational context that annotations (readOnlyHint=false, idempotentHint=false) do not convey.

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?

Front-loads the core action in the first sentence and follows with four tight sentences covering clock, ties, abstention, and verification status. No filler, though the sentence fragments are slightly telegraphic.

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 description covers matching, timebase, ties, and abstention. What is missing is sibling routing and any prerequisites around the exact-digest requirement, leaving a gap for a tool with five parameters among many frame/media 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 100%, so the schema already documents query, file_path, transcript, source_sha256, and include_image. The description adds only the mapping of "exact video digest" to the source_sha256 requirement and reinforces that the transcript is caller-supplied, so it is close to the baseline.

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 ("Select a frame by lexical transcript match") with the matching mechanism named, so the agent knows this is a transcript-driven frame selector. It does not, however, differentiate itself from nearby siblings like video_frame or video_frames, leaving the choice to inference.

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 explicit when-to-use, when-not-to-use, or alternative routing guidance. The only edge-case guidance ("A zero-token match abstains") describes failure behavior, not tool selection.

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