Enum TraceAssertion 

pub enum TraceAssertion {
    TraceMustCallTool {
        tool: String,
        min_calls: Option<u32>,
    },
    TraceMustNotCallTool {
        tool: String,
    },
    TraceToolSequence {
        sequence: Vec<String>,
        allow_other_tools: bool,
    },
    TraceMaxSteps {
        max: u32,
    },
    ArgsValid {
        tool: String,
        test_args: Option<Value>,
        policy: Option<Value>,
        expect: Option<String>,
    },
    SequenceValid {
        test_trace: Option<Vec<ToolCallRow>>,
        test_trace_raw: Option<Vec<Value>>,
        policy: Option<Value>,
        expect: Option<String>,
    },
    ToolBlocklist {
        test_tool_calls: Option<Vec<String>>,
        policy: Option<Value>,
        expect: Option<String>,
    },
}

An assertion carrying a key this enum does not define is rejected at parse time.

Without deny_unknown_fields serde drops the unrecognised key silently, and where the intended field has a default the assertion falls back to a shape that cannot fail. The documented max_calls: 0 “must NOT use a forbidden tool” example is the worked case: the key is dropped, min_calls defaults to 1 in matchers.rs, and the assertion inverts into “must be called at least once” with no signal at any stage (#1961).

deny_unknown_fields is applied at the container, which is the only place serde accepts it — it is not a variant attribute, and the compiler rejects it as one. There is folklore that container-level rejection is unreliable on an internally-tagged enum (serde-rs/serde #2294, #1358). Those defects are about unit-like variants and flatten; every variant here is a struct variant with named fields and none flattens, and rejection was verified on this exact shape for the hardest case in it — tool_blocklist, whose fields are all defaulted, so nothing but the tag is required. A stray key there is rejected too. Nested free-form values (policy, test_args) are serde_json::Value and stay unconstrained, which is intended: the guard covers the assertion’s own field vocabulary, not policy contents.

Keep the guard at the container. Per-variant allow-set validation was considered and is not needed here; the tests in tests/assertions_unknown_fields.rs pin the behaviour that makes it unnecessary, including the all-defaulted variant.

Variants

TraceMustCallTool

Fields

tool: String

min_calls: Option<u32>

TraceMustNotCallTool

Fields

tool: String

TraceToolSequence

Fields

sequence: Vec<String>

allow_other_tools: bool

TraceMaxSteps

Fields

max: u32

ArgsValid

Fields

tool: String

test_args: Option<Value>

policy: Option<Value>

expect: Option<String>

SequenceValid

Fields

test_trace: Option<Vec<ToolCallRow>>

test_trace_raw: Option<Vec<Value>>

policy: Option<Value>

expect: Option<String>

ToolBlocklist

Fields

test_tool_calls: Option<Vec<String>>

policy: Option<Value>

expect: Option<String>

Trait Implementations

impl Clone for TraceAssertion

fn clone(&self) -> TraceAssertion

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for TraceAssertion

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for TraceAssertion

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Serialize for TraceAssertion

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.