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vulnforge_fuzz_wasm_runtime

Audits WebAssembly execution engines (Wasmtime, Wasmer, WasmEdge), WASI capability preopens, and differential mutation fuzzing specs across 8 critical vulnerability vectors (CWE-119, CWE-284, CWE-400, CWE-770, CWE-698, CWE-362, CWE-459…

Instructions

Audits WebAssembly execution engines (Wasmtime, Wasmer, WasmEdge), WASI capability preopens, and differential mutation fuzzing specs across 8 critical vulnerability vectors (CWE-119, CWE-284, CWE-400, CWE-770, CWE-698, CWE-362, CWE-459, CWE-778) with automated policy synthesis and canary sandbox verification.

Input Schema

NameRequiredDescriptionDefault
formatNoWasm format (WASMTIME_CONFIG, WASMER_CONFIG, WASMEDGE_CONFIG, WASI_CAPABILITY_MANIFEST, DIFFERENTIAL_FUZZ_SPEC, WAT_MODULE) (optional)
contentNoRaw Wasm runtime config, WASI capability manifest, differential fuzz spec, or WAT module text
filePathNoFile path of Wasm configuration or WAT module (optional)
watContentNoWebAssembly text format (WAT) module content (optional)
mutationRoundsNoNumber of mutation rounds to evaluate (default: 100)
strictPreopensNoEnforce strict non-overlapping virtual directory preopens without root access (default: true)
fuzzSpecContentNoDifferential mutation fuzzing specification content (optional)
strictDifferentialNoEnforce exact trap-code and result match across all target runtimes (default: true)

Schema Changelog

Changes observed during successful MCP inspections.

  1. Addedv1.19.0

TDQS

C2.5/5.0
Behavior2/5

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, yet 'automated policy synthesis and canary sandbox verification' is unexplained jargon — it does not say whether it writes files, spawns runtimes, or is read-only. With zero required parameters, it also fails to say what happens when content/filePath/watContent are all omitted, or what the response contains.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness3/5

Is the description appropriately sized, front-loaded, and free of redundancy?

A single front-loaded sentence is efficient, but it is packed with a parenthetical list of eight CWE identifiers that displaces more useful information such as return behavior or mode selection. The CWE enumeration does not help an agent decide or invoke correctly.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness2/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For an 8-parameter tool with no annotations and no output schema, the description omits return values, side effects, mode selection across the format enum, and defaults behavior. The scope of what gets produced after 'canary sandbox verification' is entirely unstated.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so both the parameter meanings and the format enum values are already fully documented in the schema. The description adds no syntax, defaults, or interaction rules (e.g. how format selects between content, watContent, and fuzzSpecContent) beyond what the schema supplies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose3/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description names a specific resource (Wasm runtimes, WASI preopens, differential fuzz specs) but muddles the verb: the tool is named 'fuzz' yet the text leads with 'Audits', and no distinction is drawn from siblings like vulnforge_audit_wasm_ebpf or vulnforge_fuzz_api. An agent can guess the domain but not whether this is an audit or a fuzzing engine.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

There is no statement of when to use this tool, when not to, or which sibling to prefer for overlapping Wasm/eBPF or API fuzzing work. The CWE list implies an audit context but gives no routing guidance.

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