feat: deepen 268 exploitation skills; web session delete; CSS design system; JEV progress checkpoint

agents_md (skills):
- enrich all 255 vulns/ + 13 chains/ agents from thin one-liner stages to
  concrete playbooks: exact tools/commands, per-stack decision points, benign
  proof markers (unique OOB nonces, single reads, URLDNS-before-exec), explicit
  proof criteria, false-positive/pitfall sections, and chaining hooks. Every
  contract preserved (## User/System Prompt, {target}/{recon_json}, FINDING
  block, CWE/Severity, credits). avg 37->53 lines; loader parses all 449.

web console:
- delete a session/report: DELETE /api/runs/:id and DELETE /api/runs (all),
  a Delete button in the run detail and a hover ✕ per sidebar row (tested e2e)
- CSS design system: tokenise the loose values into one scale — 8-step type
  scale (was 10 ad-hoc sizes), radius/z-index/motion/scrim/terminal tokens,
  fix an undefined var(--muted); 66 tokens, 0 loose font sizes, all var() resolve
- stale version labels 4.0.0/4.2.0 -> 4.2.1

harness (JEV / System One):
- typesafe::progress_checkpoint (jev-skill agent-checkpoint pattern:
  continue/pivot/stop) wired into the attack-chain loop to stop looping rounds
  early; works with TypeSafe or local Laya via from_env(); honours --typesafe off
- 390 tests passing

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

agents_md/vulns/endpoint_flow_linker.md

@@ -8,16 +8,32 @@ You are testing **{target}** for sensitive multi-step flows built by linking end
 
 **METHODOLOGY:**
 
-### 1. Map the graph
-- Build the route/endpoint graph; note which endpoint's output (id, token, filename, URL) feeds another endpoint's input
+### 1. Build the endpoint graph
+- Enumerate routes from recon, `/openapi.json`/`/swagger`, JS bundles (regex for `fetch(`/`axios`/URL literals), HAR/proxy history. Tools: mitmproxy/Burp sitemap, `katana`/`gau` for URLs, `jq` over OpenAPI to list paths+params.
+- For each edge, record what one endpoint EMITS (id, token, `signed_url`, filename, `next_step`, order/cart id, reset token) and where another CONSUMES it. Mark producer -> consumer pairs — those seams are the targets.
 
 ### 2. Find sensitive flows
-- Trace flows through auth, password reset, payment, file up/download, account/role change, admin, export — the ones with real impact
+- Trace end-to-end flows with real impact: signup->verify, login->MFA->session, password-reset (request->token->set), checkout (cart->price->pay->confirm), file (upload->scan->publish/download), account/role change, data export, admin approval.
+- Note trust assumptions: which step assumes the previous one succeeded and who owns each object.
 
 ### 3. Attack the seam
-- Tamper the value passed between steps (swap an id/token, skip a step, replay, reorder) and see if the server accepts an invalid state; connect the finding to what it unlocks downstream
+- Tamper the inter-step value: swap an id/token to another tenant's (IDOR at the seam), reuse a one-time token, replay a completed step.
+- Skip / reorder: call the final step directly (`POST /checkout/confirm` before payment; `POST /reset/complete` without the token step; publish before scan). Does the server accept an invalid state?
+- Race / TOCTOU: fire the state-changing step twice concurrently (price recalculation, coupon, balance) — chain to a race agent if promising.
+- Parameter carry-over: change a value that step 1 set (price, role, quantity, `is_admin`) and see if step 3 still trusts the client copy.
+- PROOF: capture the full request+response chain showing the server accepted the invalid/forged state and the downstream effect (order confirmed unpaid, another user's file published, elevated role persisted).
 
-### 4. Report Format
+### 4. Pitfalls / false-positives
+- A step failing with 400/403 when tampered = the guard works; not a finding.
+- Client-side-only sequencing that the server re-validates is not exploitable — confirm the SERVER honored the skipped/forged state.
+- Reflected id != accessed data; you must retrieve/act on the cross-owned object.
+
+### 5. Chaining hooks
+- A leaked/guessable inter-step token or signed URL -> feed to IDOR/BOLA or ATO agents.
+- A session obtained mid-flow -> reuse across the rest of the graph.
+- Emit any host/creds/token discovered as inputs for the next specialist (`chains_from`).
+
+### 6. Report Format
 For each CONFIRMED finding:
 ```
 FINDING:
@@ -25,9 +41,9 @@ FINDING:
 - Severity: High
 - CWE: CWE-840
 - Endpoint: [full URL]
-- Vector: [what/where]
+- Vector: [producer step → tampered seam → consumer step]
 - Payload: [exact request / PoC file path]
-- Evidence: [raw request+response / PoC output proving it]
+- Evidence: [raw request+response chain / PoC output proving the invalid state was accepted]
 - Impact: Broken workflow → data access / privilege abuse
 - Remediation: Enforce server-side authorization & state validation at EVERY step; sign/scope inter-step tokens
 ```