BackGone Background Removal

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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds genuinely new information the annotations cannot carry: no API key or auth is required, the call is free, and it names the actual return payload (including the source URL and verification date, which signals data provenance). It does not cover error behavior for an invalid country slug.

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?

Three short sentences, front-loaded with cost and the core verb, then the empty-argument case, then the auth note. Every sentence carries a distinct fact — pricing, payload contents, listing behavior, auth — with no filler or repetition of the title.

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 correctly compensates by enumerating the returned fields, so an agent knows what it will receive without a trial call. The only remaining gap is failure behavior for a mistyped or unsupported country slug, which matters given the slug list is open-ended in the schema text.

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 both parameters are already documented, and the enum constrains locale. The description's "call without a country" guidance duplicates what the schema already says ("Omit to list all supported countries") and says nothing about the locale parameter or accepted slug format beyond what the schema shows. 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 and resource ("Returns the official passport or ID photo requirements for a country") and enumerates exactly what comes back: printed size, head height, background, digital file rules, editing policy, source URL, verification date. This is unmistakably distinct from the siblings get_pricing and remove_background, which an agent can rule out 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?

"Call without a country to list the countries covered" gives an explicit calling convention for the zero-argument case, which is the main ambiguity for a tool with zero required parameters. It also sets cost expectations up front ("Free", "No API key needed"). It stops short of stating what happens with an unsupported slug or when to prefer another tool, but the sibling set is unrelated so no routing guidance is really needed.

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 cover safety (readOnly, idempotent, non-destructive). The description adds important behavioral context not in annotations: the tool is free, requires no API key, and credits never expire. It does not describe return format or rate limits, but those are minor gaps given the simplicity.

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 short sentences with zero waste; the most important information ('Free', 'Returns prices', 'No API key') is front-loaded.

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?

The tool has one optional parameter and no output schema; the description covers what it returns, that it is free, and that no auth is needed. Combined with complete schema and annotations, nothing essential 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 coverage is 100% and the single parameter 'kind' is fully documented in the schema. The description adds no additional meaning about the parameter beyond what the schema provides, so baseline 3 is appropriate.

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 ('Returns') and resource ('BackGone prices'), and enumerates the two categories (API credit top-up packs, website subscription/credit-pack tiers). It clearly distinguishes this tool from the image-processing siblings.

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 notes 'Free' and 'No API key needed', giving useful context about when this tool can be called without authentication. However, it does not explicitly state when to prefer this tool over others (though no alternatives exist for pricing), so it stops short of full 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?

The description adds substantial context beyond the annotations: it discloses the production engine, inline return format, cost of 1 API credit on success, no charge on failure, and the required Authorization bearer key. It does not contradict the annotations declaring readOnlyHint=false, openWorldHint=true, idempotentHint=false, and destructiveHint=false.

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 description is front-loaded with the core action and return value, then quickly covers billing, authentication setup, and input exclusivity. Every sentence contributes operational information without unnecessary repetition.

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 three-parameter image-processing tool with no output schema, the description supplies everything needed to invoke it correctly: purpose, output format, authentication, credit cost, failure billing behavior, and the one-of input rule. The annotation coverage and schema descriptions handle the remaining safety and parameter details.

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 each parameter well. The description adds an important semantic constraint missing from the schema: exactly one of image_url or image_base64 must be supplied.

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 gives a specific verb and resource: it removes the background from one image and returns a transparent PNG or WebP inline. The purpose is unmistakable, though it does not explicitly differentiate itself from the sibling tools check_photo_requirements and get_pricing.

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 clearly states the input constraint that exactly one of image_url or image_base64 must be provided, and it states API-key and credit requirements. However, it gives no explicit guidance on when to use this tool versus the sibling tools or on when not to use it.

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