Bounded failures from RequestSeal.verify/3, RequestSeal.sign/4, RequestSeal.Policy.new/1, RequestSeal.Ash.scope/2, RequestSeal.Profile, quorum verification, and signature negotiation.

Every error has retryable: false, a library-generated random 16-character lowercase hex correlation, and detail: nil except the Web Bot Auth reasons listed below and :signature_base_failed, whose detail is one of these bounded signature-base reason atoms (or :nonqualifying_signature, whose detail is the rejected signature reason):

• :limit — signature-base or Structured Fields resource ceiling.
• :wrong_message_kind, :missing_request_context, :unavailable_origin, :unavailable_trailers, :missing_field — required context or field unavailable.
• :non_ascii, :unknown_field_schema, :invalid_field_schema, :invalid_structured_field, :missing_dictionary_key — field derivation rejects.
• :noncanonical_query_name, :invalid_query_encoding, :missing_query_parameter, :ambiguous_query_parameter — query derivation rejects.

No caller bytes, key identifiers, exception text, or partial verification value are kept.

Closed reasons by layer:

• :input: :invalid_message (message validation), :invalid_policy (missing choices or invalid policy), :invalid_options (invalid, duplicate, unknown, or missing options/specification), :algorithm_mismatch (signing alg differs from the explicit algorithm or accompanies JWS), :limit (wire/member/component bounds, including a decoded Signature member or nonce exceeding 1,024 bytes).
• :input additionally includes :invalid_quorum (malformed composite policy) and :invalid_profile (invalid extension profile namespace, keys, values or size, or a generic verification :profile or :principal option).
• :fields: :duplicate_parameter (repeated parameter names on signature or request members/components), :duplicate_label (repeated labels within or across occurrences), :missing_signature_input, :missing_signature (absent field), :invalid_signature_input (invalid dictionary, components or parameter types), :invalid_signature_field (invalid byte-sequence dictionary), :unknown_label (selected label absent from both), :label_mismatch (unpaired dictionary labels), :label_in_use (signing would reuse an existing label).
• Web Bot Auth :fields: :invalid_signature_agent (detail :legacy_string, :invalid_dictionary, :duplicate_member, or :invalid_member), :no_web_bot_auth_signature (no selected tag).
• Web Bot Auth :policy: :invalid_keyid (not a canonical SHA-256 thumbprint), :nested_coverage_incomplete (inner input or components absent), :test_key_rejected (published test key forbidden), :unexpected_signature (untagged label with rejection selected).
• Web Bot Auth :freshness: :lifetime_exceeded (nonpositive or excessive window).
• Web Bot Auth :key: :agent_unresolved with detail :missing_member, :unsupported_type, :not_an_origin, :untrusted_agent, :source_mismatch, :unknown_key, :revoked_key, :source_unavailable, or :timeout. These details never carry an agent URL, key ID, or nonce.
• :policy: :algorithm_not_permitted (sender alg or authoritative algorithm outside allowlist), :algorithm_mismatch (verification HTTP alg differs from the authoritative algorithm or accompanies JWS), :missing_required_component (exact identifier absent), :unexpected_component (extra identifier with rejection selected).
• :profile: extension packages document their own bounded reason atoms and details for source-specific acceptance rules.
• :key: :unknown_key (resolver returned :error), :key_resolver_failed (callback fault or malformed algorithm/key result).
• :crypto: :invalid_signature (cryptography rejects), :signature_base_failed (base construction rejects), :verifier_failed (verification callback fault, malformed result or invalid key), :signer_failed (signer fault, error, malformed result, empty signature or more than 1,024 bytes).
• Spec signing :input: :unsupported_component (unavailable covered component), :invalid_request (covered Content-Length conflicts with retained bytes).
• :content: :digest_not_covered (exact complete selected digest not signed), :digest_unsupported (no usable selected digest or invalid digest field), :digest_mismatch (checksum disagrees), :body_unavailable (required body or representation unavailable).
• :quorum: :quorum_not_met (required slots or distinct-unit count unmet), :unexpected_signature (unmatched label with rejection selected), :nonqualifying_signature (matched label failed every eligible slot; detail is its last bounded reason), :ambiguous_key_identity (trusted key equivalence unknown), :binding_unsatisfied (nested or parameter binding).
• :negotiation: :invalid_accept_signature (malformed request or unsupported parameter), :inapplicable_component (wrong target context), :negotiation_unfulfilled (eligible verified label, component set, or parameter differs), :negotiation_unfulfillable (unavailable component, incompatible chooser, unfulfillable parameter, callback fault, or signing failure).
• :freshness: :invalid_clock (fault or noninteger/out-of-range clock), :missing_created (max-age requires created), :missing_expires (required expiration absent), :created_in_future, :expired, :too_old (time checks).
• :binding: :invalid_verification (not a successful Verification with valid crypto, unevaluated authorization, and bounded current-profile facts), :invalid_binding (missing, unknown, or invalid explicit mapping choices), :unattributed (caller rejects anonymous identity), :actor_unbound (actor callback faults, returns :error, malformed data, or a nil actor), :tenant_unbound (tenant callback faults, returns :error, or malformed data).
• :replay: :missing_replay_identifier (absent or empty authenticated nonce), :commitment_failed (callback fault, error, malformed or oversized key), :replayed, :store_unavailable, :store_timeout, :store_failed (capacity, adapter fault, or contract violation). Store timeouts are indeterminate.