MimirAPI

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

With no annotations, the description carries the full burden. It does disclose output format (SVG), a scope limit ('simple chart'), and cost ('Free'), but says nothing about authentication, rate limits, how the SVG is delivered (inline string vs. URL), or chart customization constraints.

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 terse sentences, front-loaded with the core action and output format; no filler. 'Free' is minimal but earns its place as a pricing signal.

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-parameter, read-only rendering tool with no output schema, the description tells the agent what comes back (an SVG). The remaining gap is the delivery mechanism of that SVG, which is minor given the tool's simplicity.

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?

One parameter with 100% schema description coverage, so the schema already documents 'values'. The description only restates 'series of numeric values' without adding ordering, length, or empty-series behavior. Baseline 3 is correct here.

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 (render), resource (chart), output format (SVG), and input type (numeric series). Sibling tools are clearly distinct resources, so no explicit differentiation is needed; the only gap is what kinds of charts are supported.

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?

The only usage signal is the trailing word 'Free', which vaguely ties it to the pricing-oriented sibling list_premium_tools. There is no guidance on when to pick this over alternatives, nor any prerequisite 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. It usefully discloses the output format (SVG) and that the operation is free, but says nothing about image dimensions, generation latency, how named themes resolve, or any rate limits/auth needs.

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?

A single tight sentence with the purpose front-loaded. 'Free' and '(SVG)' are minor trailing extras but still load-bearing enough not to be waste.

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 simple three-param generator with no output schema, the description plus schema is minimally sufficient, but with no annotations and no enumeration of theme values it leaves the agent guessing about valid inputs and result characteristics.

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 description enumerates title, subtitle, and theme and marks the latter two optional, which is about all the schema at 67% coverage already conveys. It adds no syntax, format, or valid-value information (e.g. what theme names are accepted), so it does not compensate for the uncovered subtitle parameter.

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 (Generate) and resource (social/OpenGraph preview image) plus the concrete output format (SVG). The word 'OpenGraph' naturally separates it from siblings like generate_chart and generate_qr, though the description never explicitly names or contrasts those alternatives.

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 or when-not-to-use guidance and no named alternative, even though generate_chart and generate_qr are close siblings that an agent could confuse with this. 'Free' hints at a cost distinction (relevant given list_premium_tools) but is not framed as a selection criterion.

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?

No annotations are provided, so the description carries the burden. It usefully discloses the output format (SVG) and that there is no cost barrier, but says nothing about data length limits, generation constraints, rate limits, or whether the result is a file vs inline markup.

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, front-loaded with the core action and output format. 'Free.' is terse but carries pricing context; there is no filler or padding.

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 simple, stateless generation tool with a fully documented two-parameter schema, the description covers the essentials and even supplies the return format (SVG) in lieu of an output schema. Minor gaps remain around limits and failure modes, but nothing critical 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% with only two parameters, and the schema already documents both 'data' and the 'ecl' error-correction levels with their default. The description adds no parameter-level detail beyond the schema, so the baseline of 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 (generate), resource (QR code), output format (SVG), and accepted input (any text or URL). The resource is clearly distinct from siblings like generate_chart, generate_og_image, and screenshot_url, so an agent can route correctly 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?

The description gives a weak contextual cue ('Free') implying no premium/paid path is required, which is relevant given the list_premium_tools sibling. However, it offers no explicit when-to-use or when-not-to-use guidance versus alternatives.

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?

No annotations are provided, so the description carries the full behavioral burden. It discloses real context about the listed services (pay-per-call over x402, USDC on Base, HTTP 402 payment challenge, no signup/API key), which is genuinely useful. However, it says nothing about this tool's own behavior: whether the listing call itself is free or paid, whether it is read-only, or how results are returned.

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?

A single front-loaded sentence naming the verb and resource, followed by a short access-model clause. Dense and largely waste-free, though the parenthetical payment details could be trimmed slightly 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?

With no output schema and no annotations, the description should describe what a caller gets back, but it only names the categories of tools rather than the response shape (tool names, pricing, request schemas?), and does not resolve whether this listing call itself incurs a payment. Adequate for a zero-param catalog tool, but the return contract is left to inference.

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 takes zero parameters and the schema is fully self-describing, so there is no parameter semantics gap to fill. Baseline 4 applies; the description needs to add nothing here.

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 ('List') and resource ('MimirAPI premium pay-per-call tools') with a clear scope qualifier ('available over x402 (USDC on Base)'). The enumerated categories (price routing, sanctions screening, ephemeral Postgres, provenance certificates) make the resource concrete. It is unmistakably a discovery/catalog tool distinct from every sibling generator/validator.

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 implied by the name and nature of a catalog tool (call it to discover paid tools), but the description never states when to call this versus the sibling tools or any prerequisite. The 'No signup, no API key' clause describes the listed tools' access model, not when/how to invoke this one. No explicit when/when-not guidance is given.

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 it does disclose the safety-relevant traits: read-only rendering of a public URL, https-only restriction, no cost ('Free'), and the exact shape of the return payload (PNG plus WCAG violations with rule id, impact, fix-it link, node counts). It omits operational behavior such as timeouts, page-size limits, rate limits, and what happens on unreachable or blocked pages, which keeps it short of a 5.

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 tight sentences, front-loaded with the action and output before the value pitch. The clause 'See what a page actually looks like and what is wrong with it' is mild restatement of the preceding sentence, but 'Free.' and 'https only.' are high-value, low-cost facts.

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, so the description must describe return values, and it does so thoroughly (PNG plus structured axe-core findings). No annotations exist either, and the description covers the main behavioral envelope (read-only, public, https, free). Remaining gaps are failure modes and rate/timeout behavior rather than anything needed to form a correct 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 description coverage is 100% for the single 'url' parameter, so the schema already defines its meaning; the description only adds the 'public https' qualifier already present in the field text. Baseline 3 applies when the schema does the heavy lifting.

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 (render) plus resource (public https URL) and enumerates both outputs (full-page PNG screenshot and an axe-core accessibility audit). Nothing among the siblings (generate_chart, generate_og_image, generate_qr, validate_phone, list_premium_tools) overlaps with rendering-plus-auditing a live page, so an agent can route unambiguously.

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 clear context for use ('See what a page actually looks like and what is wrong with it, in one call') and a hard precondition ('https only', 'public' URL). It offers no explicit when-not or named alternative, but the sibling set contains no competing tool, so the missing exclusion clause costs little.

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?

No annotations are provided, so the description must carry the full behavioral burden — and it does disclose the important traits: no network call, no message sent, and that the operation is free. It stops short of describing error behavior for malformed input or any rate limits, which is the only remaining gap.

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 compact sentences with the core capability and return values front-loaded, followed by the cost and no-side-effect claims and the alternative-tool routing. No filler or restatement of the name.

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-parameter, read-only validation call with no output schema, the description supplies what is needed: the accepted input form, what is returned (country calling code and region), the absence of side effects, and the cost. Nothing an agent needs to call it correctly 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% for the single 'number' parameter, so the schema already documents the E.164-or-loosely-formatted accepted input. The description adds only marginal meaning beyond that baseline, so a 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?

States a specific verb and resource ('Validate a phone number') and enumerates the exact checks performed: E.164 well-formedness plus country calling code and region extraction. The scope is precise enough that an agent can distinguish it from any carrier/line-type lookup 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?

Explicitly routes the agent: this tool is for 'pure format + country check', and for carrier/line type (mobile / landline / VoIP) the description names a distinct paid phone-intel alternative. Both the when-to-use and the when-to-use-something-else conditions are stated, not inferred.

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