Base Tx Preflight
Server Details
Simulate a Base tx before signing: revert reason, gas limit, full fee in ETH/USD. Paid x402.
- Status
- Healthy
- Last Tested
- Transport
- Streamable HTTP · MCP 2025-11-25
- URL
- ChatGPT
- –
- Claude
- –
TDQS
Scored across 2 tools
The two tools have related but distinguishable purposes: preflight_validate checks input formatting before payment, while preflight_quote returns pricing and the x402 request needed to buy the actual preflight. The shared 'preflight_' prefix and both being free checks could cause brief confusion, but the descriptions make the boundary clear.
Both tool names follow a strict preflight_<verb> pattern, using consistent snake_case and clear action verbs. There is no mixed convention or ambiguity in the naming scheme.
Only two tools are present, which feels thin for a transaction preflight service even if the paid operation is handled externally via x402. The set is minimal but not obviously over-scoped.
The surface covers validation and quoting/purchase instructions, but it lacks a tool that actually performs or retrieves the Base transaction preflight result. Agents can prepare and pay but cannot complete the core workflow through the MCP tools alone.
Available Tools
2 toolspreflight_quoteQuote a Base tx preflightBInspect
Free: price, payTo and the exact x402 request to buy a Base transaction preflight (simulation with decoded revert, gas limit, full fee in ETH/USD).
| Name | Required | Description | Default |
|---|---|---|---|
| to | Yes | ||
| data | No | ||
| from | No | ||
| value | No |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the behavioral burden and discloses important traits: the call is free, it returns pricing and payment details, and it produces an x402 request for a paid preflight that includes simulation, decoded revert, gas limit, and fees. It does not explicitly state that it is read-only or side-effect-free, but the quote framing makes that largely clear.
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 efficient sentence that front-loads the key fact that the quote is free and then lists the returned components and the preflight features being priced. Every clause adds useful context, with no filler or 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?
Given no annotations, 0% parameter schema coverage, and no output schema, the description should do more to explain how to call the tool and what the parameters mean. It adequately describes the quote outputs and the paid preflight service, but the missing parameter guidance and lack of alternative-tool routing leave it incomplete 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?
Schema description coverage is 0%, so the description must compensate for undocumented parameters. It provides only the context that these are Base transaction fields; it does not explain what to, data, from, or value mean, nor their formats or constraints, so the parameter semantics remain largely unspecified.
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 and returned quote components: price, payTo, and the exact x402 request to buy a Base transaction preflight. It is clear this is a pricing/quote tool rather than a validation tool, though it does not explicitly name or differentiate from the sibling preflight_validate.
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 the tool is used when an agent needs a free quote before buying a Base transaction preflight, and it notes that the quote is free. However, it gives no explicit when-not guidance and does not mention the preflight_validate alternative, leaving the routing decision mostly implied.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
preflight_validateValidate tx inputBInspect
Free: checks from/to/data/value formatting and whether 'to' is a contract on Base, before you pay.
| Name | Required | Description | Default |
|---|---|---|---|
| to | Yes | ||
| data | No | ||
| from | No | ||
| value | No |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full behavioral burden. It usefully discloses that the call is free and read-only in effect, what it inspects, and that it targets Base specifically — genuinely useful facts not present in structured fields. It stops short of saying what the result looks like (pass/fail shape, error reasons) or what happens on an invalid address, which matters for a validation 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?
One compact sentence with the cost qualifier front-loaded, then the checks, then the timing rationale. Nothing is redundant. The only weakness is that brevity edges toward terseness — 'before you pay' is a little elliptical about what payment is being referred to.
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 four-parameter tool with no annotations, no output schema, and no parameter descriptions, the definition should say more about the result of validation and about acceptable input formats. It covers the what and the why-plus-when adequately, so an agent can decide to call it, but not fully how to interpret or shape the 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 0%, so the description must compensate. It does name all four parameters (from/to/data/value) and tells the agent they are checked for formatting, which is more than the bare schema offers. But it never states expected formats — hex address form, 0x-prefixed calldata, or whether value is wei or a decimal string — leaving the agent to guess what input will pass.
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 pair: it validates the formatting of the to/from/data/value fields and checks whether 'to' is a contract on Base. That is concrete enough to distinguish it from a quoting tool, and the 'before you pay' clause implies the ordering relative to preflight_quote, though it never names the sibling explicitly.
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 'before you pay' implies this is a pre-transaction sanity check that precedes a quote or send, which is useful sequencing context. However, it never states when NOT to use it, never names preflight_quote as the alternative, and gives no prerequisites such as a required chain or address format.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Tool Schema Changelog
Recent tool additions, removals, and schema changes observed during successful MCP inspections.
2 tool updates
- First observed
preflight_quote - First observed
preflight_validate
Related MCP Connectors
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justhandledofficial
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