clr-activation-debugging

# CLR Activation Debugging Agent uses this skill to identify why the .NET Framework shim selected, failed to select, or suppressed a CLR. ## When to Use | User prompt | Use | |---|---| | User reports `0x80131700` or `Unable to find a version of the runtime to use` | Agent uses this skill | | User reports unexpected or suppressed Feature on Demand dialogs | Use this skill | | User reports wrong CLR selection for native EXE, COM, or legacy host APIs | Use this skill | ## When Not to Use | User prompt | Route | |---|---| | User targets modern .NET or CoreCLR | Agent uses a modern .NET diagnostics workflow | | User reports assembly binding defects after CLR load | Agent uses Fusion diagnostics | | User reports a runtime crash after successful CLR load | Agent uses crash diagnostics | ## Required Inputs | Input | Required | Notes | |---|---|---| | `*.CLRLoad*.log` files | Yes | Agent waits for process exit before reading the files. | | Symptom and HRESULT | Yes | Agent records the visible defect and error code. | | Registry and launch context | Recommended | Agent uses this input for SEM and registration checks. | ## Workflow | Step | Agent action | Test | Pass | |---|---|---|---| | 1 | Agent enables CLRLoad logging with the exact `COMPLUS_CLRLoadLogDir` or registry path and verifies the log directory exists first. | Read the environment variable or registry value and the directory path. | Logging points to an existing directory. | | 2 | Agent reproduces the defect and collects log files after process exit. | Read `*.CLRLoad*.log` in the target directory. | At least one log file exists for the failing process. | | 3 | Agent scans literal decision markers. | Run `Select-String -Path *.log -Pattern "Decided on runtime:","ERROR:","Launching feature-on-demand","Potential feature-on-demand launch","V2.0 Capping"`. | Output contains the decision-path lines or confirms their absence. | | 4 | Agent traces entry point, config, policy, SEM state, and CLSID registration. | Read matching log lines and registry keys under `HKLM\SOFTWARE\Microsoft\.NETFramework\` and `HKCR\CLSID\{guid}\InprocServer32`. | Diagnosis names the exact lines and registry facts that drove the result. | | 5 | Agent applies the narrowest fix and reruns the scenario. | Reproduce with the same launch path. | `Decided on runtime:` changes as intended or the error disappears. | | 6 | Agent removes temporary logging settings after capture. | Read the environment variable or registry path again. | Temporary logging state is removed or documented for cleanup. | ## Common Pitfalls | Pitfall | Agent fix | |---|---| | Agent reads the log before process exit | Agent waits for process exit because the file stays open. | | Agent changes registry paths or literal message text | Agent preserves the exact paths and message fragments. | | Agent skips SEM state for Feature on Demand cases | Agent records the parent-process error mode. | | Agent fixes assembly binding instead of CLR activation | Agent routes assembly binding defects to Fusion diagnostics. | ## Decision Matrix | Symptom | Likely cause | Agent action | |---|---|---| | `0x80131700` with no usable runtime | Legacy bind plus missing .NET 3.5 or missing config | Agent installs the required runtime or adds config that points to v4. | | Unexpected Feature on Demand dialog | Legacy COM activation plus dialog-allowed SEM state | Agent fixes registration or runtime policy and records SEM state. | | Suppressed Feature on Demand message | Parent process sets `SEM_FAILCRITICALERRORS` | Agent records the inherited SEM state and adjusts the parent path when the prompt includes that scope. | | Wrong CLR selected | Config order, policy, or host API request favors another runtime | Agent corrects config or host policy. | | Mixed v2 and v4 loads | Separate activation paths exist in one process | Agent aligns host policy or startup config. | ## Validation Checklist - [ ] Agent verified the log directory before enabling logging. - [ ] Agent collected `*.CLRLoad*.log` files after process exit. - [ ] Agent cited literal decision lines from the logs. - [ ] Agent cited matching registry or SEM facts. - [ ] Agent reran the scenario after the fix. - [ ] Agent removed temporary logging settings or documented cleanup. ## Additional source coverage The selected version is the preferred starting point by the recorded date/context basis. Distinct source coverage is retained in the scoped references; do not apply superseded or conflicting defaults automatically. - [clr-activation-debugging-alternative-1](references/contexts/clr-activation-debugging-alternative-1/guide.md) - [clr-activation-debugging-alternative-2](references/contexts/clr-activation-debugging-alternative-2/guide.md) - [clr-activation-debugging-alternative-3](references/contexts/clr-activation-debugging-alternative-3/guide.md) - [clr-activation-debugging-alternative-4](references/contexts/clr-activation-debugging-alternative-4/guide.md) - [clr-activation-debugging-alternative-5](references/contexts/clr-activation-debugging-alternative-5/guide.md)