Enum ValidationError 

pub enum ValidationError {
    UnknownSection {
        key: String,
        entity_type: String,
        declared: Vec<String>,
        suggestion: Option<String>,
    },
    UnknownMetadata {
        key: String,
        entity_type: String,
        declared: Vec<String>,
        suggestion: Option<String>,
    },
    InvalidEnumValue {
        field: String,
        value: String,
        allowed: Vec<String>,
        field_description: Option<String>,
        suggestion: Option<String>,
        type_write_rules: Vec<String>,
        entity_type: String,
    },
    ReadOnlyField {
        field: String,
    },
    SectionNotUpdatable {
        section: String,
        entity_type: String,
    },
    InvalidRelationshipType {
        input: String,
        allowed: Vec<RelationshipHint>,
        suggestion: Option<String>,
    },
    InvalidRelationshipShape {
        rel_type: String,
        from_type: String,
        to_type: String,
        allowed_source_types: Vec<String>,
        allowed_target_types: Vec<String>,
        suggestion: Option<RelationshipHint>,
    },
    SectionContentInvalid {
        section: String,
        embedded_heading: String,
    },
    SectionContentControlByte {
        section: String,
        control_char: char,
        codepoint: u32,
        byte_offset: usize,
    },
    InvalidFieldValue {
        field: String,
        value: String,
        expected_type: String,
        expected_format: Option<String>,
        field_description: Option<String>,
        entity_type: String,
    },
}

A typed CRUD-time validation failure. Mirrors the wire-format error codes the MCP layer surfaces; the engine adapters convert each variant into their own error type.

Variants

UnknownSection

UNKNOWN_SECTION: section key not declared on the type and not absorbed by a catch_all section.

Fields

key: String

entity_type: String

declared: Vec<String>

suggestion: Option<String>

UnknownMetadata

UNKNOWN_METADATA: metadata key not declared on the type.

Fields

key: String

entity_type: String

declared: Vec<String>

suggestion: Option<String>

InvalidEnumValue

INVALID_ENUM_VALUE: enum-typed metadata field rejected the supplied value.

Fields

field: String

value: String

allowed: Vec<String>

field_description: Option<String>

suggestion: Option<String>

type_write_rules: Vec<String>

entity_type: String

ReadOnlyField

READ_ONLY_FIELD: caller tried to set or unset a read-only metadata key (mem, id, type) on update.

Fields

field: String

SectionNotUpdatable

SECTION_NOT_UPDATABLE: the section is not in the type’s updatable_fields allowlist, or it is the virtual relationships surface (which is managed by memstead_relate, not memstead_update).

Fields

section: String

entity_type: String

InvalidRelationshipType

INVALID_REL_TYPE: the relationship name is not declared in the active schema and the schema runs in strict mode. Open-mode schemas admit unknown names with a warning instead — see [check_relationship_strict_or_open].

Fields

input: String

allowed: Vec<RelationshipHint>

suggestion: Option<String>

InvalidRelationshipShape

INVALID_REL_SHAPE: the edge’s (from_type, to_type) pair violates the schema’s declared source_types / target_types for this relationship. Only fires for shape-pinned edges; an edge with empty constraint lists admits any pair.

Fields

rel_type: String

from_type: String

to_type: String

allowed_source_types: Vec<String>

allowed_target_types: Vec<String>

suggestion: Option<RelationshipHint>

SectionContentInvalid

SECTION_CONTENT_INVALID: a section body contains a ^## line (level-2 heading) which the entity’s compose-then-reparse pipeline would interpret as a section delimiter. Without this guard a caller can inject content into a different section by embedding a heading in another section’s body. Deeper headings (### and below) are allowed — the parser anchors only on level 2.

Fields

section: String

embedded_heading: String

SectionContentControlByte

SECTION_CONTENT_INVALID (control-byte sub-case): a section body contains a control character other than tab (\t) or newline (\n). A NUL especially makes git classify the .md blob as binary, defeating the diffable-markdown invariant the storage model rests on, and downstream text tooling truncates at it. Shares the wire code with the heading-injection case (both are SECTION_CONTENT_INVALID) — the control_char/byte_offset recovery fields discriminate it from embedded_heading. Mirrors the title control-char guard (refuse with an actionable hint, not silent strip). \t and \n stay legal; the verbatim-escape contract is untouched (this screens a byte class, it does not de-escape).

Fields

section: String

control_char: char

The offending control character (a char, since the body is already valid UTF-8 — a NUL is U+0000).

codepoint: u32

Its Unicode scalar value, surfaced as a number for unambiguous machine reading (the string form JSON-escapes).

byte_offset: usize

Byte offset into the section body — matches the od -c view a caller uses to locate the byte.

InvalidFieldValue

INVALID_FIELD_VALUE: a non-enum typed metadata field received a value that does not parse as its declared type — a Date field given "not-a-real-date" or "", or a Number field given non-numeric text. Distinct from INVALID_ENUM_VALUE (the key and type are valid but the value is out of an enum’s vocabulary) and UNKNOWN_METADATA_FIELD (the key is not declared): here the key and field-type are valid but the value is malformed for the type. Without this check the value round-trips raw and corrupts range-filter results (a non-date string sorts lexically against real dates, so *_after matches it).

Fields

field: String

value: String

expected_type: String

expected_format: Option<String>

field_description: Option<String>

entity_type: String

Implementations

impl ValidationError

pub fn code(&self) -> &'static str

Stable UPPER_SNAKE_CASE wire code for this validation sub-variant. Single source of truth — both EngineError::code() (via the Validation(_) arm) and the MCP validation_envelope mapper read from here, so the wire code cannot drift between channels.

pub fn details(&self) -> Value

Structured recovery payload for this validation sub-variant. The payload mirrors the variant’s declared fields so callers branching on code can read the same shape validation_envelope ships on the MCP wire. Returned shape is documented in the MCP tool descriptions — see Errors: blocks on memstead_create / memstead_update / memstead_relate.

pub fn prose_render(&self) -> String

Render rich, fully-inlined recovery prose for the agent-visible text channel. Closes the asymmetry where warnings render their structured details inline but errors collapse details.X references to a “+N more — see details.X” pointer pointing at a channel the agent’s MCP client doesn’t surface to the model. The structured details() channel is unchanged — this method only governs result.content[0].text. Display stays terse for logs and tracing::warn! consumers.

Trait Implementations

impl Clone for ValidationError

fn clone(&self) -> ValidationError

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ValidationError

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

Formats the value using the given formatter.

impl Display for ValidationError

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

Formats the value using the given formatter.

impl Error for ValidationError

fn source(&self) -> Option<&(dyn Error + 'static)>

Returns the lower-level source of this error, if any.

fn description(&self) -> &str

👎Deprecated since 1.42.0:

use the Display impl or to_string()

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

fn provide<'a>(&'a self, request: &mut Request<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access)

Provides type-based access to context intended for error reports.

impl From<ValidationError> for EngineError

fn from(source: ValidationError) -> Self

Converts to this type from the input type.