OG Stamp

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

With no annotations, the description carries the full burden and does disclose meaningful traits: authentication is mandatory, the call is metered ('One credit'), the return is a hosted URL, and there is a limitation ('Does not return a free hotlink'). It omits failure behavior, whether credits are spent on error, and supported page requirements, so it is good but not complete.

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, each earning its place: purpose and return value first, then the auth/cost constraint, then the negative caveat. Nothing is padded or redundant.

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 tool with no annotations and no output schema, the description reasonably covers purpose, auth, cost, and return format. It still leaves gaps: no distinction from render_og_image, no explanation of the four styling parameters, and no note on error or credit-refund behavior, which matters for a metered call.

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 only 33% across 6 parameters, so the description would need to compensate. Instead it only reiterates url and api_key (both already documented in the schema) and says nothing about font, size, theme, or layout, whose enums are unlabeled and offer no guidance on defaults or effect.

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 concrete verb and resource ('Build a hosted Open Graph card from a public page') and names the extracted fields, so the agent knows exactly what it produces. It does not, however, distinguish itself from the sibling 'render_og_image', which sounds like the same operation, leaving the agent to guess which to call.

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 supplies real invocation constraints (requires api_key, costs one credit, no free hotlink) which guide usage, but it never states when to prefer this tool over render_og_image or og_pricing. The routing decision between the near-identical siblings is left entirely to inference.

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?

With no annotations, the description carries the full burden. It discloses key behavioral traits: credits never expire and it is a one-time PayPal payment, not a subscription. However, it does not describe the return value or any side effects beyond that, leaving some behavioral uncertainty for a simple tool.

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 consists of three concise sentences, each contributing distinct information: the core action, the credit validity, and the payment model. It is front-loaded with the primary purpose and contains no filler.

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 zero-parameter tool with no output schema, the description covers the essential purpose and key constraints. It could specify the return format or clarify what a 'credit pack' entails, but given the simplicity, it is largely complete for correct invocation.

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?

The tool has zero parameters, so the schema covers everything (100%). The description adds no parameter-specific information, but there is nothing to document; the baseline of 4 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 clearly states the action ('Return') and the resource ('OG Stamp credit packs'). It implicitly differentiates from the image-related siblings by focusing on credits, making the tool's purpose unambiguous.

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?

No guidance is provided on when to use this tool versus alternatives. The description mentions product features (credits never expire, PayPal one-time) but does not situate the tool's use case or explicitly compare with siblings, leaving the agent to infer usage context.

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?

With no annotations, the description carries the full burden and does reasonably well: it discloses the auth requirement (ogs_ key), the billing model (one credit per image), that the result is hosted and stable, and a negative constraint ("Does not return a free hotlink"). It stops short of describing failure modes, image retention, or rate limits beyond credits.

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 and return value, with no filler. The final sentence ("Does not return a free hotlink") is slightly cryptic and would benefit from sharper wording, but it does convey a real constraint.

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?

There is no output schema, so the description correctly spends words on the return value (the hosted PNG URL). Combined with 100% schema coverage and stated auth/cost, an agent has enough to call it correctly; only persistence and error behavior are unaddressed.

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 13 well-described params including 4 enums, so the schema already does the heavy lifting and a baseline of 3 applies. The description adds no parameter-level detail beyond restating that api_key is required and costs a credit, which the schema already says.

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 uses a specific verb plus resource ("Build a hosted Open Graph PNG") and even states the return artifact (a stable https://ogstamp.com/i/{id}.png URL for og:image), which is more than most definitions offer. It does not explicitly contrast itself with the sibling og_image_from_url, so the agent must infer the params-vs-URL distinction from the names alone.

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?

Prerequisites are stated (api_key from the pricing page, one credit per image), which implies the cost/auth context for use. However, there is no explicit when-to-use guidance and no mention of when to prefer the sibling og_image_from_url or og_pricing, so the routing decision is left to inference.

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