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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered structurally. The description still adds real value beyond them: the player auto-loads paused, success does not confirm rendering or playback, and availability is bounded by the returned expiresAt and the original companion connection. This is solid added context, but it does not reach the depth of an unannotated mutation tool's disclosures.

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?

The core action is front-loaded in the first sentence and follow-ups are short and purposeful (prerequisite, caveat, client compatibility, persistence). It is dense with distinct facts, though a couple of clauses about saving and availability could be tighter without losing meaning.

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?

No output schema exists, and the description compensates fully: it names the prerequisite sibling call, the client-dependent previewUrl fallback, the paused-until-Play behavior, the non-confirmation caveat, and the expiresAt/connection-bound availability. An agent has everything needed to call it correctly and interpret the outcome.

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 coverage is 100%, so both parameters are already fully documented, including the UUID formats and the reuse/refresh rules. The description restates the same guidance ("original connection and operationId", "call once") without adding syntax or format detail beyond the schema, so the baseline 3 applies.

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: present the MP4 produced by a completed ceraph_record_run operation. It also explicitly distinguishes itself from recording behavior ("No new recording is made") and from the screenshot sibling by naming the media type, so an agent can route without opening the schema.

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?

Gives explicit ordering and preconditions: poll remote_status for completion first, then call once with the original connection and operationId. It also states the failure mode (do not infer rendering failure from missing confirmation) and the fallback for non-MCP-Apps clients, leaving nothing to inference.

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