Engineering / R&DManaged AI Agents

Engineering / R&D AI Agents,
Monitored for Security

Nestack Agent Care helps engineering teams monitor, evaluate, and optimize AI agents used for code generation, review, secrets handling, and production operations — before small AI errors become security or reliability incidents.

126failure modes
57SEV-1 failure modes
750+baseline eval cases
24/7Agent Monitoring

Scope

Engineering / R&D AI agents we build & manage

Twelve archetypes — from code review to autonomous coding, migrations and FinOps.

Observability

What we make observable

Every engineering agent session is traced across ten layers — what we capture and the evidence we keep.

  1. Evidence we keep
    Goalconstraintsapproval requirement
  2. Evidence we keep
    Sourceversiontimestamprelevancecitation
  3. Evidence we keep
    Planned sequenceactual sequenceworkflow status
  4. Evidence we keep
    Task statusresultretryfailure reason
  5. Evidence we keep
    Tool nameversioninputoutputpermissionresult
  6. Evidence we keep
    Model/versioninput/outputtoken usagelatencycost
  7. Evidence we keep
    Evaluation typemetricthresholdresult
  8. Evidence we keep
    Guardrail targettriggeractionenforcement result
  9. Evidence we keep
    Reviewerdecisioncorrectionreason
  10. Evidence we keep
    Outcome statusbusiness resultlinked trace

Catalog

Failure modes

Filter failure modes by where they occur in the agent lifecycle—from goals and retrieval to tools, evaluations, guardrails and outcomes.

Nothing on this page matches that. Try a layer (tool, retrieval, guardrail), a code, or a severity.

0 documented↑↓ move · ↵ open · ⌘↵ filter matrix
126 documented · select a cell to filter
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ENG-01Insecure code suggestions — injection flaws, authz gaps, crypto misuseSEV-1
ENG-02Secret and credential leakage in code, logs or answersSEV-1
ENG-03License contamination — copyleft code in proprietary reposSEV-2
ENG-04Hallucinated APIs, packages or dependencies (slopsquatting risk)SEV-2
ENG-05Ungated destructive actions — prod DBs, deletions, force-pushesSEV-1
ENG-06IP exfiltration — proprietary code sent to unapproved externalsSEV-1
ENG-07Injection via repo content, issues and PR descriptionsSEV-1
ENG-08Test false-passes — assertions that can’t failSEV-2
ENG-09Pipeline tampering by suggestion — workflows edited to skip checks or widen permissionsSEV-1
ENG-10Incident misdiagnosis — confident wrong root cause extends outagesSEV-2
ENG-11Silent breaking changes — API contracts changed without versioning or migration notesSEV-2
ENG-12Vulnerability-triage false-negatives — exploitable findings closed as noiseSEV-1
ENG-13Infrastructure cost blowups — runaway CI, orphaned resources, oversized instancesSEV-3
ENG-14Agent memory poisoning — planted instructions persist across sessionsSEV-1
ENG-15MCP / tool-chain supply-chain compromise — poisoned tool descriptions, malicious servers & skills, name-squattingSEV-1
ENG-16MCP rug-pull — tool silently mutated after one-time approval (TOCTOU trust swap)SEV-1
ENG-17Instruction-file backdoor — hidden-Unicode directives in CLAUDE.md, .cursorrules, copilot-instructionsSEV-1
ENG-18Agent sandbox & network-egress escape — file writes or traffic break isolationSEV-1
ENG-19Over-privileged agent identity, sprawl & confused-deputy token reuseSEV-1
ENG-20Post-destruction fabrication & cover-up — agent conceals damage it causedSEV-1
ENG-21Autonomous recovery escalating to destruction — “self-heals” a minor error into a catastrophe, then defies standing limitsSEV-1
ENG-22Acting on hallucinated state — no read-after-write verification before chained mutationsSEV-2
ENG-23Reward-hacking generalizing to deception & monitor sabotageSEV-1
ENG-24Silent model-version drift — provider swap shifts behavior with no code changeSEV-2
ENG-25Multi-agent coordination failure — conflicting / overwriting edits & semantic contradictionsSEV-2
ENG-26Runaway autonomous loop — unbounded token burn on no-progress cyclesSEV-3
ENG-27Code-churn inflation — AI changes reverted or rewritten within days (premature-revision rework)SEV-2
ENG-28Clone proliferation & maintainability decay — duplication up, refactoring collapses, modules only the AI understandsSEV-2
ENG-29Rubber-stamp approval & reviewer-fatigue overload — AI PRs merged without meaningful human reviewSEV-2
ENG-30Developer skill atrophy — delegation erodes debugging & comprehension over timeSEV-2
ENG-31Hallucinated / stale documentation & deprecated-pattern relianceSEV-2
ENG-32Context-window truncation — lost requirements cause wrong or incomplete edits in large reposSEV-2
ENG-33Shadow & orphaned agents — unsanctioned or ownerless agents keep running with live credentialsSEV-2
ENG-34Unauditable / non-reproducible agent decisions — no record of model, context or approverSEV-2
ENG-35Cross-agent cascade — one agent’s error propagates through chained automationsSEV-1
ENG-36Vendor dependency — provider outage halts pipelines; retained prompts create discovery exposureSEV-3
ENG-37Research-agent result fabrication — autonomous experiments game their own evaluation harnessSEV-2
ENG-38Hallucinated citations & prior art — fabricated references reach research reports or patent filingsSEV-1
ENG-39Export-control breach — ITAR/EAR-controlled R&D data sent to AI tools (deemed export)SEV-1
ENG-40Fine-tuning data / model poisoning — backdoors implanted into proprietary internal modelsSEV-1
ENG-41Physically invalid generative design — AI CAD/formulations pass geometry checks but fail engineering validitySEV-1
ENG-42Trade-secret disclosure & AI-inventorship defects — prompts leak inventions; thin human contribution risks patent validitySEV-2

A · Code-generation & review copilots

QR-03Stale branch context01 · RetrievalSEV-3
QR-04Resemblance missed at drafting02 · ReasoningSEV-1
QR-06Retired setting read as live02 · ReasoningSEV-1
QR-02Thin suggestion passed forward03 · Tool / writeSEV-1
QR-05Hunk bound to the wrong change03 · Tool / writeSEV-2
QR-01Committed, provenance detached04 · OutputSEV-2
QR-07Silent filter drift05 · Change / VersionSEV-2

B · Test-writing agents

QS-03Contract inferred, not read01 · RetrievalSEV-3
QS-04Assertion froze the defect02 · ReasoningSEV-1
QS-06Fixture masks the case02 · ReasoningSEV-1
QS-02Merged without a person03 · Tool / writeSEV-1
QS-05Test weakened silently03 · Tool / writeSEV-2
QS-01Approved unread04 · OutputSEV-2
QS-07Silent coverage drift05 · Change / VersionSEV-2

C · CI/CD & deployment assistants

QU-03Stale build input read01 · RetrievalSEV-3
QU-04Promotion asserted, not evidenced02 · ReasoningSEV-1
QU-06Retired pipeline rule read as live02 · ReasoningSEV-1
QU-02Thin promotion passed forward03 · Tool / writeSEV-1
QU-05Artefact bound to wrong environment03 · Tool / writeSEV-2
QU-01Released, build unrecorded04 · OutputSEV-2
QU-07Silent pipeline drift05 · Change / VersionSEV-2

D · Documentation agents

QW-03Stale source read01 · RetrievalSEV-3
QW-04Claim asserted, not evidenced02 · ReasoningSEV-1
QW-06Superseded page read as current02 · ReasoningSEV-1
QW-02Thin page passed forward03 · Tool / writeSEV-1
QW-05Revision bound to wrong page03 · Tool / writeSEV-2
QW-01Published, release unrecorded04 · OutputSEV-2
QW-07Silent currency drift05 · Change / VersionSEV-2

E · Incident-response copilots

QX-03Stale telemetry read01 · RetrievalSEV-3
QX-04Conclusion drafted from absence02 · ReasoningSEV-1
QX-06Retired escalation rule read as live02 · ReasoningSEV-1
QX-02Thin finding passed forward03 · Tool / writeSEV-1
QX-05Finding bound to wrong incident03 · Tool / writeSEV-2
QX-01Stated, sources unrecorded04 · OutputSEV-2
QX-07Silent statement drift05 · Change / VersionSEV-2

F · Autonomous coding agents

QY-03Stale scope read01 · RetrievalSEV-3
QY-04Task widened beyond its grant02 · ReasoningSEV-1
QY-06Retired grant read as live02 · ReasoningSEV-1
QY-02Thin change passed forward03 · Tool / writeSEV-1
QY-05Change merged to the wrong target03 · Tool / writeSEV-2
QY-01Merged, nobody read it04 · OutputSEV-2
QY-07Silent scope drift05 · Change / VersionSEV-2

G · Dependency-upgrade agents

QZ-03Stale registry read01 · RetrievalSEV-3
QZ-04Bump asserted, not verified02 · ReasoningSEV-1
QZ-06Retired upgrade rule read as live02 · ReasoningSEV-1
QZ-02Fresh version passed forward03 · Tool / writeSEV-1
QZ-05Bump bound to wrong dependency03 · Tool / writeSEV-2
QZ-01Merged, publisher unrecorded04 · OutputSEV-2
QZ-07Silent upgrade drift05 · Change / VersionSEV-2

H · Vulnerability-autofix agents

RB-03Advisory read stale01 · RetrievalSEV-3
RB-04Wrong defect patched02 · ReasoningSEV-1
RB-06Fix bundled with a feature02 · ReasoningSEV-1
RB-02Merged without a person03 · Tool / writeSEV-1
RB-05Embargo broken by the diff03 · Tool / writeSEV-2
RB-01Green suite, live defect04 · OutputSEV-2
RB-07Silent rollout drift05 · Change / VersionSEV-2

I · Code-migration & modernization agents

RI-03Baseline taken from the spec01 · RetrievalSEV-3
RI-04Meaning drifts, value holds02 · ReasoningSEV-1
RI-06Dormant path reactivated02 · ReasoningSEV-1
RI-02Cut over without a person03 · Tool / writeSEV-1
RI-05Retention clock reset03 · Tool / writeSEV-2
RI-01Accepted, baseline unrecorded04 · OutputSEV-2
RI-07Silent equivalence drift05 · Change / VersionSEV-2

J · Root-cause-analysis (SRE) agents

RW-03Stale evidence read01 · RetrievalSEV-3
RW-04Cause asserted, not evidenced02 · ReasoningSEV-1
RW-06Retired review rule read as live02 · ReasoningSEV-1
RW-02Thin review passed forward03 · Tool / writeSEV-1
RW-05Review bound to wrong incident03 · Tool / writeSEV-2
RW-01Signed, evidence unrecorded04 · OutputSEV-2
RW-07Silent conclusion drift05 · Change / VersionSEV-2

K · Cloud cost-optimization (FinOps) agents

RX-03Stale duty read01 · RetrievalSEV-3
RX-04Duty left out of the costing02 · ReasoningSEV-1
RX-06Retired floor read as live02 · ReasoningSEV-1
RX-02Thin saving passed forward03 · Tool / writeSEV-1
RX-05Action lands on the wrong resource03 · Tool / writeSEV-2
RX-01Applied, no duty weighed04 · OutputSEV-2
RX-07Silent duty drift05 · Change / VersionSEV-2

L · Tech-debt refactoring agents

RZ-03Caller inventory incomplete01 · RetrievalSEV-3
RZ-04Corrected while restructuring02 · ReasoningSEV-1
RZ-06Unused code called dead02 · ReasoningSEV-1
RZ-02Merged without a person03 · Tool / writeSEV-1
RZ-05Engine transformation wrong03 · Tool / writeSEV-2
RZ-01Merged, list unrecorded04 · OutputSEV-2
RZ-07Silent scope creep05 · Change / VersionSEV-2

Guardrails

Critical guardrails for Engineering agents

Ten controls that hold regardless of prompt, plan or pressure. Open one to see what it protects, what trips it, what the agent is forced to do, who may release it, and what is written to the record.

GR-01No production mutation without change-ticket approvalOverride defined
  1. Target

    Production databases, deployments, force-pushes, deletions and infrastructure state across live environments.

  2. Trigger

    Any write, delete or deploy targeting a production resource without an approved change ticket.

  3. Action — enforced

    Platform blocks execution, converts the step to a staged plan, and requires the ticket reference before release.

  4. Human override

    Release manager via approved change ticket linked in the deploy pipeline.

Logged evidencechange ticket id · target resource · diff hash · approver identity · execution timestamp · rollback plan id

GR-02No agent egress beyond the sandbox allow-listNo override
  1. Target

    Network calls, file writes and artifact uploads from agent sandboxes and CI runners.

  2. Trigger

    Traffic or file output addressed outside the pinned per-task allow-list.

  3. Action — enforced

    Platform drops the connection, freezes the sandbox for forensics, and lets the task resume only on allow-listed destinations.

  4. Human override

    None — cannot be overridden in session

Logged evidencesandbox id · destination address · payload size and hash · task id · freeze timestamp

GR-03No instruction embedded in repo content, issues or PRs executedNo override
  1. Target

    Source files, README text, issue threads, PR descriptions and instruction files agents ingest.

  2. Trigger

    Directive text or hidden-Unicode payloads detected in repository or tracker content.

  3. Action — enforced

    Platform treats the content as data only, quarantines the artifact, and blocks writes to agent memory and instruction files.

  4. Human override

    None — cannot be overridden in session

Logged evidenceartifact hash · payload excerpt · repo and ref · quarantine id · scanner version

GR-04No plaintext secret in code, logs or answersOverride defined
  1. Target

    Generated code, commit diffs, CI logs, chat answers and artifact stores agents produce.

  2. Trigger

    A credential-pattern match in any agent output before write or send.

  3. Action — enforced

    Platform redacts the match, blocks the commit or reply, and opens a rotation task for the exposed credential.

  4. Human override

    Security engineer via confirmed false-positive disposition in the secret scanner.

Logged evidencedetection id · secret fingerprint · output channel · rotation ticket · block timestamp

GR-05No unreviewed edit to CI workflow definitionsOverride defined
  1. Target

    Pipeline YAML, branch-protection rules, runner permissions and check configurations in every repo.

  2. Trigger

    An agent-authored change touching workflow files, permission scopes or required checks.

  3. Action — enforced

    Platform splits the change into a separate PR, requires platform-team review, and blocks self-merge by any agent identity.

  4. Human override

    Platform engineering lead via CODEOWNERS-enforced review on the workflow PR.

Logged evidencePR id · workflow diff hash · permission delta · reviewer identity · merge timestamp

GR-06No tool call on a mutated tool manifestOverride defined
  1. Target

    MCP servers, tool descriptions, skills and connectors registered for agent use.

  2. Trigger

    A manifest hash differing from the version approved at registration time.

  3. Action — enforced

    Platform refuses the call, disables the tool fleet-wide, and requires re-approval of the changed manifest by security.

  4. Human override

    Security engineering via re-pinned manifest approval in the tool registry.

Logged evidencetool id · approved hash · observed hash · disable timestamp · re-approval record

GR-07No export-controlled data sent to external modelsOverride defined
  1. Target

    ITAR and EAR technical data, controlled designs and trade-secret material in prompts or uploads.

  2. Trigger

    A classification tag or control marking detected in content bound for an external endpoint.

  3. Action — enforced

    Platform blocks the transfer, keeps processing on approved in-boundary models, and notifies the export-control officer.

  4. Human override

    Export-control officer via documented licence determination for the specific dataset.

Logged evidencecontent classification · destination endpoint · block timestamp · requester identity · determination reference

GR-08No dependency added without registry provenance verificationOverride defined
  1. Target

    Package manifests, lockfiles, imports and build scripts across all repositories.

  2. Trigger

    A suggested package absent from the approved registry or below the age-and-adoption floor.

  3. Action — enforced

    Platform blocks the install, checks the name against known-good packages, and proposes a vetted alternative in the PR.

  4. Human override

    Staff engineer via allow-list addition recorded with a provenance review.

Logged evidencepackage name and version · registry check result · typosquat distance · PR id · approver identity

GR-09No closure of exploitable findings without sign-offOverride defined
  1. Target

    SAST, DAST, dependency and pentest findings in the vulnerability queue.

  2. Trigger

    An agent disposition of not-exploitable or wontfix on a finding above severity threshold.

  3. Action — enforced

    Platform holds the closure, requires a security engineer’s sign-off with rationale, and keeps the finding open meanwhile.

  4. Human override

    AppSec lead via documented risk acceptance with an expiry date.

Logged evidencefinding id · severity · proposed disposition · sign-off identity · rationale hash · expiry date

GR-10No merge without meaningful human review attestationOverride defined
  1. Target

    Agent-authored pull requests to protected branches across product and infrastructure repositories.

  2. Trigger

    A merge attempt where review time, diff coverage or comments indicate rubber-stamping.

  3. Action — enforced

    Platform blocks the merge, records model, prompt and context versions, and assigns a second reviewer with a review checklist.

  4. Human override

    Engineering manager via attested review confirmation on the pull request.

Logged evidencePR id · reviewer identity and dwell time · model and prompt versions · checklist result · merge timestamp

Oversight

Human review — triggers, decisions and evidence

When a defined risk trigger fires, the affected action is routed to a named reviewer. Every decision is recorded with its correction, escalation and final outcome for full traceability.

  • ConfidenceLow-confidence root cause
  • Financial impactInfrastructure spend change
  • Identity / change riskPermission or token change
  • Irreversible actionProduction write or deletion
  • Policy riskLicence or export conflict
  • Safety controlGuardrail override
  • Quality failureFailed critical evaluation
Humanreviewnamed reviewer
  • Revieweridentity + role
  • Decisionapprove / reject / amend
  • Correctionwhat changed
  • Escalationwho, why and severity
  • Final outcomereleased / blocked / returned for rework

7 triggers · any one halts the agent

1 record · 5 fields, every time

Compliance

Regulatory mapping

  • 01 Goal
  • 04 Task
  • 05 Tool
  • 06 LLM
  • 07 Evaluation
  • 08 Guardrail
  • 09 Human review
  • 10 Outcome

Security baseline

OWASP-class vulnerabilities in generated code are the department’s highest-volume risk.

Lifecycle layer:04 Task · 06 LLM · 07 Evaluation

  • ENG-01

Evaluations

Baseline evaluation suite — in detail

Baseline evaluations are completed during onboarding and repeated based on the selected plan. Agents that fail critical checks remain restricted until they pass re-testing.

Detailed case sets
37
Failure modes covered
42
Retired & rotated / quarter
10%
Audit-ready scorecard
Monthly

Output evaluation5 suites · 320 cases

150 casesSecure-code generationcatches ENG-01
40 casesIncident-replay setcatches ENG-10
40 casesContract-diff setcatches ENG-11
50 casesVuln-triage setcatches ENG-12
40 casesAssertion-integrity setcatches ENG-08

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  1. Department lead review

    For applicable high-risk agents, the client’s designated department leader reviews the evaluation criteria and pass thresholds before baseline approval.

  2. Test-case rotation

    Evaluation cases are refreshed regularly to reduce memorisation and maintain reliable performance measurement.

  3. Scorecard integration

    Scorecards track results against the approved baseline and flag material declines for review and escalation.

  4. Department-specific extensions

    Where included in scope, evaluations may be expanded using approved workflows, tools, templates, policies, and incident history.

Monitoring

Change-aware monitoring

When agent performance changes, Nestack correlates the shift with changes to the agent, prompt, model, tools, knowledge base, guardrails and evaluation suite.

Version changes by layer
01AgentAgent changed in week 5
02PromptPrompt changed in week 3Prompt changed in week 9
03ModelModel changed in week 7Model changed in week 12
04ToolTool changed in week 8Tool changed in week 10
05Knowledge-baseKnowledge-base changed in week 4
06GuardrailGuardrail changed in week 6
07Eval-suiteEval-suite changed in week 11
Safe-suggestion rate92–100%
  • Week 1 · 98.3%
  • Week 2 · 98.2%
  • Week 3 · 98.4%
  • Week 4 · 98.3%
  • Week 5 · 98.5%
  • Week 6 · 98.3%
  • Week 7 · 98.4%
  • Week 8 · 93.3%
  • Week 9 · 93.1%
  • Week 10 · 98.3%
  • Week 11 · 98.4%
  • Week 12 · 98.5%

Week readouthover or select

Week 8of 12

  • 04Tooltools 11.3

93.3%Safe-suggestion rate

  • 7 layers stamped on every run · 12-week window
  • Catches ENG-11 · silent breaking API changes

Something missing?

Don’t see your agent’s issue here?

Every AI environment is different. Share what you’re seeing, and we’ll review the behaviour, assess the risk and recommend the evaluations or controls that may help.

Report an agent issue

Tell us what you’re seeing

The more specific, the faster we can reproduce it. Playbook: Engineering / R&D

We reply within one business day.

See pricing

No commitment. Even if you never become a client, we’ll tell you what we think is happening.

Process

Universal incident runbook

Severity is assigned based on business impact, customer harm, data exposure, operational disruption and overall scope.

  • SEV-1 Critical
  • SEV-2 Major
  • SEV-3 Moderate
  • SEV-4 Minor
STEP 01

Automated monitoring or human review identifies unusual behaviour. Alerts are recorded and routed according to severity.

Cost control

Keep engineering / r&d AI agent costs under control

Token spend is monitored, optimised and reported as part of Agent Care — and savings never come at the expense of quality, because every change is verified against your evaluation baseline.

We review token spend by agent, workflow, model, and session so you can understand where AI costs are coming from.

Running engineering / r&d AI agents in production?

Get a free assessment of one agent. We’ll review its behaviour, run a baseline evaluation and highlight potential risks and performance gaps.

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