Vigil Website MCP

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

Annotations already declare this a mutating, open-world, non-idempotent operation, so the bar is lower. The description adds genuinely useful context beyond that: 'This tool does not charge anything' discloses that payment is deferred to the Stripe-hosted page, and it clarifies the external flow (buyer redirected to continue_url). No contradiction with annotations — readOnlyHint=false aligns with 'Start a purchase.'

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 sentences, roughly 35 words, with the action front-loaded first and each sentence earning its place: what it does, what to do with the result, and a non-obvious behavioral guarantee (no charge). Zero filler or repetition of schema/annotation content.

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 two-parameter tool with no output schema, the description covers the essential return value (continue_url) and the required follow-up action, which is the main thing an agent needs to know. The only notable omission is the semantics of the optional quantity parameter and any failure-mode hints, but neither is critical for a correct first 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?

Schema description coverage is 0%, so the description must compensate; 'one offer' does associate offer_id with the purchase, and the enum values are self-descriptive. However, the quantity parameter is never addressed semantically — nothing clarifies what quantity means (e.g., number of licenses) beyond the schema's default and bounds. The description partially compensates but leaves a real gap.

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 action ('Start a purchase of one offer') on a clear resource (a Stripe-hosted checkout for an offer) and explains the key deliverable (a continue_url for the buyer). This cleanly separates it from all siblings — get_checkout reads, list_products lists, read_page/search_pages/site_info are informational reads — so an agent can pick it out 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 clear usage context: initiate a purchase and send the buyer to the returned continue_url to pay, with the clarifying note that this tool does not charge anything. It stops short of explicitly naming alternatives or when-not-to-use conditions, but the create-vs-read distinction across the sibling set is self-evident and the follow-up workflow is explicit.

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 readOnlyHint, idempotentHint, and non-destructiveness. The description adds the precondition that the checkout must have been started by create_checkout, but does not disclose response contents or error behavior, which is acceptable given the strong annotation coverage.

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 communicates both the action and the required precondition with no filler. Every word serves a purpose.

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 read operation with one obvious identifier parameter and rich annotations, the description is sufficiently complete. It could mention the return shape, but the title already indicates status and no output schema is present.

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?

With only one parameter, checkout_id, the schema name is self-explanatory and the description confirms it identifies the checkout to read. However, schema description coverage is 0%, and the description itself adds no parameter-level detail, so it only earns average credit.

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 action ('Read'), a resource ('checkout'), and explicitly ties the tool to create_checkout, distinguishing it from the creating sibling. The title reinforces that it reads checkout status.

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 clearly implies the tool is used after create_checkout has started a checkout. It doesn't explicitly name alternatives or exclusions, but the relationship to its creator sibling provides sufficient context for appropriate selection.

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 the safety profile is fully covered. The description adds genuine behavioral context beyond those flags: prices are Stripe-verified, availability is live, and the response covers billing terms and delivery – all useful for interpreting the result.

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?

One sentence that front-loads the core purpose ('everything an agent can buy from Vigil') and then appends the qualifying details. Every phrase earns its place; there is 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?

For a zero-parameter, read-only catalog with annotations covering safety, the description tells the agent what to expect: the full product list, price verification, billing terms, delivery, and live availability. No output schema exists, and the description adequately fills that gap; nothing essential is missing for an agent to decide whether to call this 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?

The input schema is empty, so there are no parameters to document and schema description coverage is trivially 100%. With zero parameters, the description is not obliged to explain inputs; it correctly focuses on the returned content, hitting the baseline of 4.

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, actionable resource: everything an agent can buy from Vigil, with concrete fields (Stripe-verified prices, billing terms, delivery, live availability). This clearly distinguishes it from the sibling tools, which concern checkout (create_checkout, get_checkout) or page/document operations (read_page, search_pages, site_info).

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 implies usage context – consult this catalog when the agent needs to know what can be purchased and its pricing or terms – but it never states an explicit when-to-use or when-not-to-use. There is no alternative named and no direct pointer to create_checkout for the actual purchase flow.

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 establish readOnly, idempotent, and non-destructive behavior. The description adds useful behavioral context: the output is Markdown or stripped text, limited to 40,000 characters, and restricted to the blvigil.com domain. No contradiction with 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?

A single, front-loaded sentence communicates the action, scope, format, and limit with no filler. Every element earns its place.

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 one-parameter read-only tool, the description covers domain, output format, and truncation limit, which is sufficient context given the annotations and sibling tools. It could clarify the absent format-selection parameter, but nothing essential is missing for basic 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 schema only defines url as a URI, and schema description coverage is 0%, so the description must compensate. It adds meaningful domain and single-page context, but it does not explicitly explain how the url parameter maps to the Markdown/text output choice or how an agent should obtain a valid page URL.

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 (read), a clear resource (one blvigil.com page), and the output form (Markdown or stripped text) with a length cap. This distinguishes it from sibling tools like search_pages, which search rather than read.

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 phrase 'Read one https://blvigil.com page' clearly signals the tool is for fetching a single page from a specific domain Pitch. It does not explicitly name alternatives or state when not to use it, but the context is clear enough for an agent to route correctly beside search_pages and site_info.

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 the safety profile is covered structurally. The description adds genuinely useful context—sitemap-based search and that results carry a match score—but does not go deeper into edge cases, score semantics, or result-set behavior. No contradiction with 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, front-loaded sentences with zero waste. The purpose, domain, search method, and return promise are each conveyed in a single efficient statement.

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 read-only, idempotent search with 2 parameters (1 required) and no output schema, the description covers the domain, the search method, and the return shape (URL + match score)—essentially all a caller needs. The only gap is the lack of detail on how the match score is computed or ordered.

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?

With 0% schema description coverage, the description must compensate. It usefully explains that query means words matched against URL paths, giving meaning to an otherwise bare string parameter. However, the limit parameter is never mentioned in the text, so it relies entirely on the schema's default/min/max.

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 ('Find pages on blvigil.com'), the search field ('by words in their URL path'), the method ('sitemap search'), and the output ('Returns URLs with a match score'). This clearly distinguishes it from sibling read_page (fetch one known page) and site_info (site metadata) without needing to open 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?

The 'sitemap search' qualifier and the blvigil.com scoping imply it is for broad keyword-based lookup across the site's pages. However, it never names alternatives or states when NOT to use it (e.g., 'for a known URL, use read_page instead'), so usage guidance is implied rather than explicit.

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 traits (read-only, idempotent, non-destructive, open-world). The description adds useful context about the kind of content returned (links to sitemap, docs, contact, discovery documents), but it does not disclose output structure or other behavioral details. This is acceptable given the strong annotation coverage.

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 a single clear sentence that front-loads the tool's purpose and adds the key resource links without waste. Every part contributes 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 parameters, no output schema, and read-only annotations, the description is nearly sufficient for an agent to know when to call the tool and what it will receive. It could mention the output form, but for a simple information tool this is a minor gap.

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, so there is no parameter burden for the description to carry. Schema coverage is effectively complete, and the description does not need to explain parameter meanings it does not have.

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 tool's purpose: it explains what Vigil (blvigil.com) is and provides links to key resources like the sitemap, docs, contact, and discovery documents. It is specific about the resource and scope, and it is easily distinguishable from siblings like create_checkout or list_products.

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 makes the tool's context clear: use it when you need site-level information or discovery resources for Vigil. It does not explicitly name alternatives or state when not to use it, but the distinct subject matter and sibling list make the usage context fairly obvious.

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