Vigil Website MCP

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

With no annotations, the description carries the full burden but does add two important behavioral facts: the tool returns a continue_url for the buyer and does not charge anything. It still omits auth requirements, session expiration, idempotency behavior, and failure modes.

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 the core purpose and followed by the return value and key caveat. No wasted words, though the final sentence could be folded more smoothly into the previous one.

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 creation tool with no output schema and no annotations, the description covers the core action and return value. It remains incomplete on parameter meanings and on when to use this tool instead of siblings like get_checkout.

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 explain the two parameters. It only implies offer_id via 'one offer' and says nothing about the allowed enum values or the quantity parameter's default, minimum, or maximum.

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 ('Start a purchase of one offer') and distinguishes itself from get_checkout by being the creation action. However, it does not name or compare against any sibling tool, so the differentiation is implied rather than explicit.

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 explains the post-call flow (send the buyer to continue_url) but gives no guidance on when to choose this tool versus get_checkout, list_products, or any alternative. No when-not or prerequisite context is provided.

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 burden. 'Read' weakly implies a non-mutating operation, but the description says nothing about required authentication, error or expiry behavior, or whether the checkout is retrieved as a live or frozen snapshot.

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 well-formed sentence with zero filler, and the resource is front-loaded after the verb. It is arguably over-terse for a tool whose domain is ambiguous, but nothing in it is wasted.

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 with no output schema and no annotations, the definition is minimally adequate: it establishes the lookup key and the relationship to create_checkout. It omits the return shape, error semantics, and id format, which an agent would need to use it confidently.

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 'checkout_id' is a bare string with no description. The tool description adds no format, provenance, or validity information (e.g. whether the id comes from create_checkout's response), so the agent must guess the parameter's shape.

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 ('Read') and resource ('checkout'), and explicitly ties the tool to its sibling 'create_checkout', which helps an agent place it in the lifecycle. It stops short of 5 because it never clarifies what a 'checkout' represents in this domain (order? cart? grant?), so the resource remains somewhat abstract.

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 rather than stated: the phrase 'started with create_checkout' signals that this tool is the read counterpart to a creation flow. There is no explicit when-to-use, no exclusions, and no guidance on what to do if the checkout does not exist or is expired.

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 nature of the returned content (verified prices, billing terms, delivery, live availability) which implies a read-only catalog. However, it says nothing about authentication requirements, rate limits, caching of 'live' availability, or pagination.

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 with no filler; the resource is stated first and qualifying details follow. Every clause conveys information about what the listing returns.

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 tool with no output schema, the description doubles as a return-value summary by naming the fields available. What remains missing is positioning within the checkout flow and any access constraints, but the core is covered.

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 the baseline of 4 applies. There is nothing parameter-wise for the description to clarify, and it correctly avoids inventing filter semantics.

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 names the resource ('everything an agent can buy from Vigil') and enumerates the returned fields (Stripe-verified prices, billing terms, delivery, live availability), so the agent knows this is the product catalog listing. The verb is implied rather than stated, and it does not distinguish itself from siblings like get_checkout or 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?

There is no when-to-use or when-not-to-use guidance. It never says this should be called before create_checkout, nor how it differs from get_checkout or search_pages, leaving the agent to infer the entry point into the 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?

With no annotations, the description carries the full burden, and it does disclose two genuinely useful traits: the output format (Cloudflare Markdown for Agents) and a hard 40,000-character truncation cap. However, it never explains how the Markdown-vs-text choice is made (there is no format parameter), nor any auth, rate-limit, or failure behavior.

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 with no padding. The parenthetical '(Cloudflare Markdown for Agents)' is implementation detail that adds length without resolving the format ambiguity, keeping it just short of a 5.

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 tool with no output schema, the description covers scope, format, and size cap. It leaves gaps on how the two output formats are selected and on error/auth behavior, which matter 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?

Only one parameter exists at 0% schema coverage, and the description constrains it to a single 'https://blvigil.com' page, which adds a useful domain constraint beyond the bare uri format in the schema. It still does not clarify URL syntax or whether non-blvigil URLs are rejected.

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 (Read) and resource (one blvigil.com page) and names the output format, so the agent knows it fetches a single page rather than searching like the sibling search_pages. It does not explicitly distinguish itself from siblings, and the 'Markdown ... or stripped text' alternative is left unexplained.

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 no when-to-use, when-not-to-use, or alternative routing despite siblings like search_pages and site_info. Usage is only implied by the word 'Read'.

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 exist, so the description carries the full burden. It discloses the operation is a lookup and that results include a match score, which is useful, but says nothing about permissions, throttling, pagination, or absence of side effects beyond the implied read nature.

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 with zero filler; the purpose and behavior are front-loaded and the return hint is appended economically.

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 annotations and no output schema, the description covers enough to call the tool but leaves gaps: the 'limit' parameter is unexplained and the scope is limited to blvigil.com without clarifying coverage. Adequate but not complete for a search tool with an undocumented parameter.

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 0%, so the description must compensate. It explains the 'query' parameter reasonably ('words in their URL path') but never addresses 'limit' (default 20, max 50) or what a match score means, leaving one of two parameters entirely undocumented.

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 ('Find pages') and the matching mechanism ('by words in their URL path (sitemap search)'), which is concrete enough to distinguish it from read_page and site_info. It does not, however, explicitly name those siblings or contrast the modes, so it stops short of the top score.

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 when-to-use guidance and no mention of alternatives, even though read_page and site_info are obvious neighbors an agent must choose between. The '(sitemap search)' parenthetical implies the mechanism but not when to prefer this over fetching a page directly.

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 supplied, so the description carries the burden. It does disclose the nature of the response (identity plus links to sitemap, docs, contact, discovery documents), which is meaningful behavioral context, but says nothing about whether it is read-only, side-effect free, or requires authentication.

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 sentence with no waste; the core purpose (what Vigil is) is front-loaded and the enumeration of returned links follows immediately. Every clause 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?

With no output schema and no annotations, the description must cover the return value, and it does so at a high level by naming the categories of links returned. It is nearly complete for a trivial zero-argument discovery tool, with only minor ambiguity about the exact response shape.

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 the baseline is 4. There is nothing parameter-related the description could or should add, and the schema correctly declares an empty object with additionalProperties false.

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 resource (site information for Vigil/blvigil.com) and enumerates the payload: sitemap, docs, contact and discovery documents. It is clear what an agent gets back, though it does not explicitly contrast itself with siblings like read_page or search_pages.

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 guidance on when to call this tool versus read_page or search_pages, nor any prerequisite or exclusion. The agent must infer that this is the entry-point/discovery tool from the description alone.

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