# find-CServerSideClientBase_GetUserIDString

> Final-guarantee fallback for CServerSideClientBase_GetUserIDString when its deterministic string-xref preprocessor cannot resolve the function. Locate the concrete user-ID formatting helper in engine2.dll / libengine2.so and write the semantic artifact for the active platform. Trigger: CServerSideClientBase_GetUserIDString

- Skill: `hlnd2t/find-cserversideclientbase-getuseridstring` (Agent Skill)
- Install (CLI): `npx skillmds@latest add hlnd2t/find-cserversideclientbase-getuseridstring`
- Raw SKILL.md: https://api.skillmd.com/api/skills/hlnd2t/find-cserversideclientbase-getuseridstring/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: HLND2T (https://skillmd.com/u/hlnd2t)
- Updated: 2026-09-22
- Page: https://skillmd.com/skills/hlnd2t/find-cserversideclientbase-getuseridstring

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# Find CServerSideClientBase_GetUserIDString (Agent fallback)

Use this fallback only after `ida_preprocessor_scripts/find-CServerSideClientBase_GetUserIDString.py` fails.
The target is the `CServerSideClientBase` member that returns/formats a client's user-ID string; it is not the
nearby network-ID helper, HLTV/replay formatter, or a console command.

## Step 0. Skip an existing output

If `CServerSideClientBase_GetUserIDString.<platform>.yaml` already exists as a non-empty mapping in the active
artifact module directory, skip it. Never derive the artifact path from `bin` or write into checkout expected
artifacts while analyzing.

## Step 1. Locate the target in IDA

Search the current binary for exact string literals matching the user-ID fallback values:

- `STEAM_ID_LAN`
- `STEAM_ID_PENDING`
- `HLTV`
- `REPLAY`
- `UNKNOWN`

Enumerate code xrefs and decompile candidate functions. Prefer the function whose first argument is the
`CServerSideClientBase` object (`rcx` on Windows, normally `rdi` on Linux) and which returns or writes the
formatted user ID. The deterministic finder intentionally excludes unrelated matches such as `%.3f min`,
`for %.2f minutes`, `removeid:  couldn't find %s`, `FULLMATCH:%s %s`, and `banid 0 %s`.

Confirm the candidate's semantics: it reads the client's identity/auth state, selects a fallback such as
`STEAM_ID_LAN`, `STEAM_ID_PENDING`, `HLTV`, `REPLAY`, or `UNKNOWN`, and returns the resulting string (or a
pointer to it). Reject functions that only produce the network ID, register a command, or log a diagnostic.
The old build-14167 values are orientation only; do not copy an address without checking the current binary.

## Step 2. Generate and write the artifact

Rename the verified function with IDA MCP. Use `/generate-signature-for-function` to generate a unique
signature from the current function body, then use `/write-func-as-yaml` with:

- `func_name=CServerSideClientBase_GetUserIDString`
- verified current `func_addr`
- `func_rva` relative to the current image base
- current `func_size`
- validated `func_sig`

Write only the active platform output:

- `CServerSideClientBase_GetUserIDString.windows.yaml` beside `engine2.dll`
- `CServerSideClientBase_GetUserIDString.linux.yaml` beside `libengine2.so`

The trusted analyzer performs final canonical serialization; this skill supplies semantic fields only.

## Failure handling

- If no candidate combines the identity fallbacks with `CServerSideClientBase` receiver semantics, stop and
  report the ambiguity rather than guessing from reference addresses.
- Never emit a Windows result while analyzing Linux, or vice versa.
- If the output cannot be uniquely signed, retain only fields accepted by the analyzer's schema and report why
  the signature was omitted; do not invent a signature.