--- name: logic-locate description: "Locate the root cause of a CONFIRMED failure via backward-then-forward semi-formal tracing." risk: safe source: https://github.com/hyhmrright/logic-lens/tree/main/skills/logic-locate source_repo: hyhmrright/logic-lens source_type: community date_added: 2026-07-01 license: MIT license_source: https://github.com/hyhmrright/logic-lens/blob/main/LICENSE --- # Logic-Lens — Fault Locate ## When to Use Use this skill when you need locate the root cause of a CONFIRMED failure via backward-then-forward semi-formal tracing. Trigger when the user provides a stack trace, failing assertion, error message, or specific wrong-value observation — "find the bug", "this test is failing", "track down this crash", "why is... ## Setup Use lazy loading per `../_shared/common.md` §13: 1. Read `../_shared/common.md` only for language, Iron Law, Fault Confidence, scope routing, Remedy discipline, config fields, and loading budget. 2. Read only the relevant step in `logic-locate-guide.md` as you reach it. 3. Load `../_shared/logic-risks.md`, `../_shared/semiformal-guide.md`, `../_shared/semiformal-checklist.md`, and `../_shared/report-template.md` on demand when the current step needs them. ## Process **Step 0. Language + scope routing.** Detect language per `common.md` §1. Confirm a concrete failure exists (stack trace, failing assertion, specific wrong value). If only a suspicion, switch to logic-review. **Step 1. Understand the failure** (guide Step 1) — observed behavior, expected behavior, reproduction path. **Step 2. Identify the entry point** (guide Step 2) — failing test, outermost application frame, or request handler — whichever is closest to the failure. Stay inside the failure cone first: stack frames, failing test fixture, directly called local functions, and config/env values read on that path. Do not scan unrelated modules unless the trace crosses into them. **Step 3. Trace backward from the failure point** (guide Step 3) — walk each value and state back to its origin, building premises at every hop. **Step 4. Trace forward to confirm** (guide Step 4) — from the suspected root, verify the trace reaches the observed symptom. **Step 5. Interprocedural tracing if a callee is implicated** (guide Step 5) — trace into the callee; check return values under observed conditions, unhandled exceptions, shared-state mutation. Apply the depth limit and Call-Chain Context Label format defined in `semiformal-guide.md` §Call-Chain Context Labels; at the limit, state the remaining callee path as a premise assumption and downgrade to **Medium confidence** (per `common.md` §7). **Step 6. Identify the root divergence and classify** (guide Step 6) — state the exact line/expression, the violated premise, the actual behavior, the propagation chain to the symptom; pick the L-code. **Step 7. Output the focused report** (guide Step 7) — Fault Confidence (High/Medium/Low, per `common.md` §7); Primary Fault (single five-field finding); optionally Contributing Factors; a minimal Remedy per `common.md` §10. **Format is mandatory even for simple one-function bugs: always emit the labeled Premises / Trace / Divergence / Trigger / Remedy fields and the Fault Confidence line. Never answer with a plain fix suggestion.** **Mode line in report:** `Fault Locate` (Chinese: `故障定位`). **Output format:** the Findings section has ONE Primary Fault, not a full Critical/Warning/Suggestion split. The Logic Score line is replaced by **Fault Confidence:** High / Medium / Low. ## Limitations - Use this skill only when the task clearly matches its upstream source and local project context. - Verify commands, generated code, dependencies, credentials, and external service behavior before applying changes. - Do not treat examples as a substitute for environment-specific tests, security review, or user approval for destructive or costly actions. The `../_shared/` files referenced above are not bundled. Do not claim their scoring, L-code taxonomy, templates or source coverage were applied. The local guide can support a standalone logic-location review: state the inspected scope, quote the concrete source location, explain the observed symptom and consequence, propose a proportionate remedy and list uninspected paths. Do not invent source attributions or framework codes. Obtain the missing material before any step that depends on it. --- Source attribution: hyhmrright/logic-lens contributors, via Agentic Awesome Skills Original project: https://github.com/hyhmrright/logic-lens License: MIT + CC-BY-4.0 License information: https://creativecommons.org/licenses/by/4.0/ Original upstream instructions; downloaded from Mega AI Hub. ## Upstream license notice MIT License Copyright (c) 2026 Logic-Lens Contributors Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. # Mega AI Hub resource metadata Creator / publisher: hyhmrright/logic-lens contributors, via Agentic Awesome Skills Original project: https://github.com/hyhmrright/logic-lens Attribution basis: Recorded upstream repository Fields of work: Development & Engineering Roles: Software Developer Specialties: Specialty not specified Tools: Tool not specified Country applicability: Country not specified Classification basis: Dave AI task classification from package title, description, and declared metadata Instruction SHA-256: bf2bc6ee1e486e9359d792f0d25af8f8e50fc30ef583eff8395709a45adef591 Metadata reviewed: 2026-10-27 This metadata supersedes earlier Mega AI Hub catalog attribution. 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