Animated Explainer Video Maker: Motion Graphics, No Presenter - ManyMotions

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

Beyond the annotations (readOnly=false, idempotent=true, destructive=false, openWorld=true), it discloses credit consumption, that the cost was shown at prepare time, that the run takes minutes and requires polling, and that it needs a signed-in account. These are meaningful behavioral traits annotations cannot express.

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?

Four short sentences, front-loaded with the core action, then progressively disclosing cost, latency/polling, and auth. No filler and every sentence carries operational 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?

With an output schema present, return values need no explanation, and cost/latency/auth are all covered. The only gap is that the required project_id parameter is left entirely to the schema, which itself has no description.

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 0% and the single parameter (project_id) is never mentioned or explained in the description. The phrase 'the prepared run' hints at what is being started but gives no syntax, format, or constraint for the required project_id.

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?

The description states a specific verb and resource ('Start the prepared run') and situates it in a workflow, distinguishing it from the sibling get_result ('poll with get_result') and from the prepare step ('prepared run'). An agent can tell it apart from both siblings without opening a 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?

It gives an explicit precondition ('Call it only after the user explicitly asked to generate'), names the alternative for the follow-up step ('poll with get_result'), and states the auth condition ('the client asks the user to sign in when it is missing'). When-to-call, what-not-to-do, and the next-tool routing are all covered.

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

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

Annotations already declare readOnlyHint=true, idempotentHint=true and destructiveHint=false, so 'Read-only: it never starts or changes a run' largely restates structured data. The description does add behavioral context about the response content (URLs for audio, images or video) and the 'when it is done' completion condition, which is modest added value on top of the annotations.

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 tight sentences, the purpose front-loaded in the first clause and the safety guarantee second. No filler and nothing to trim.

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-value detail is not strictly required, and annotations cover the safety profile, making the description nearly sufficient for a one-parameter tool. The only real gap is the unexplained project_id, which leaves a small hole for an otherwise simple tool.

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 0% for the single required project_id, and the description never mentions the parameter at all. With no compensation for the coverage gap, the agent gets no meaning beyond the bare property name and type.

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 ('check the progress of a run') and the payoff ('return the URLs of the finished files'), and implicitly separates itself from generate_result by noting it 'never starts or changes a run'. An agent can distinguish polling from generation without opening either 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?

Usage is only implied: the polling/progress framing suggests it is called after a run has been started, and the 'never starts or changes a run' clause hints that generate_result is the starter. But no sibling is named and there is no explicit when-to-use, when-not-to-use, or polling-cadence guidance.

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

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

Adds substantive behavior beyond the annotations: no generation occurs, no credits are consumed, no sign-in is required, and the call returns settings plus the credits that would be required. Annotations only supply the generic safety profile (readOnlyHint=false, destructiveHint=false), so this cost/no-op disclosure is genuinely additive. Mild tension with readOnlyHint=false exists, but since 'prepare' can create a preparation artifact, this is not a contradiction.

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-loaded with purpose and deliverable, then constraints, which is the right order. It loses a point for redundancy: 'no presenter on camera' appears twice and the 'original visuals only' constraint partially restates the earlier exclusions.

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?

For a single-required-parameter preparation tool with an output schema present, the description covers everything an agent needs: what is produced, what is not produced, cost implications, auth requirements, and content restrictions. Return values are already handled by the output schema, so nothing material is missing.

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%, with topic, style, and audience all documented in-schema, so the baseline is 3. The description's video traits (30 seconds, four scenes, voiceover) inform output expectations rather than adding meaning to any parameter, so it does not exceed 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 and resource ('Prepare an animated explainer video'), and pins down the concrete deliverable: ~30 seconds, four illustrated scenes with motion and voiceover, no presenter, one MP4. This is specific enough that an agent can distinguish it from the sibling generate_result/get_result tools without opening a 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?

Explicit when-to-use ('new animated videos from text only, with no presenter on camera') and explicit when-not ('do not use it for uploaded footage, photos, real people, editing or captions'). It also clarifies the boundary with generation ('Nothing is generated and no credits are spent'), which is exactly the disambiguation an agent needs against generate_result.

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