Invoking Gemini CLI

Delegate QAQC, code review, and analysis tasks to Gemini CLI using markdown files for input and output. Write review criteria to REVIEW.md, invoke Gemini, then read FINDINGS.md for results.

Pattern: Markdown File Handoff

code

Claude Code                         Gemini CLI
    |                                   |
    +-- Write REVIEW.md ----------------+
    |   (code + review criteria)        |
    |                                   |
    +-- Execute: gemini -y "Read        |
    |   REVIEW.md, analyze, write       |
    |   findings to FINDINGS.md"        |
    |                                   |
    |                                   +-- Reads REVIEW.md
    |                                   +-- Analyzes content
    |                                   +-- Writes FINDINGS.md
    |                                   |
    +-- Read FINDINGS.md <--------------+
    |   (analysis + recommendations)    |
    v                                   v

Benefits:

•Eliminates shell escaping issues
•Keeps context structured in reviewable files
•Enforces explicit output structure
•Supports session resume

Model Selection

Model	Use Case	Status
`gemini-3-pro-preview`	Default. Strong reasoning	CLI default
`gemini-3-flash-preview`	Large context, fast analysis	For big codebases

Recommendation: Use default gemini-3-pro-preview for most tasks. Switch to gemini-3-flash-preview for very large context (>100K tokens) via -m flag.

Note: If you encounter 429 capacity errors with gemini-3-pro-preview, retry or wait briefly.

Invocation

Standard Pattern (Recommended)

bash

cd /path/to/project && gemini -y "Read REVIEW.md in the current directory. Follow the review criteria. Write all findings to FINDINGS.md."

With Explicit Model

bash

cd /path/to/project && gemini -y -m gemini-3-flash-preview "Read REVIEW.md, analyze per criteria, write findings to FINDINGS.md"

Resume Session

bash

gemini -r <session_id> "Read REVIEW.md for updated criteria, append to FINDINGS.md"

Core Flags Reference

Flag	Purpose
`-y`	YOLO mode - auto-approve all actions
`-m <model>`	Model: `gemini-3-pro-preview`, `gemini-3-flash-preview`
`-r <id>`	Resume session by ID
`--output-format json`	JSON output for parsing
`--list-sessions`	List available sessions

Review Request Template (REVIEW.md)

markdown

# Review Request: [Brief Title]

## Objective
[What kind of review/analysis is needed]

## Review Criteria
Rate each finding: CRITICAL | HIGH | MEDIUM | LOW

### Security
- SQL injection vulnerabilities
- XSS risks
- Authentication/authorization issues
- Hardcoded secrets

### Reliability
- Error handling gaps
- Edge cases not covered
- Race conditions
- Resource leaks

### Performance
- N+1 query patterns
- Unnecessary allocations
- Missing caching opportunities

### Maintainability
- Code clarity
- Naming conventions
- Documentation gaps

## Code to Review

### File: src/api/users.ts
```typescript
// Paste code here or reference file

File: src/services/auth.ts

typescript

// Paste code here

Context

[Any relevant background, constraints, or requirements]

Output Format

Write to FINDINGS.md with:

•Summary of review
•Findings table with severity, location, description
•Specific recommendations
•Overall assessment
•Session ID for follow-up

code


## Findings Template (FINDINGS.md)

Instruct Gemini to produce:

```markdown
# Review Findings: [Title]

## Summary
[Brief overview of review results]

## Findings

| Severity | Location | Issue | Recommendation |
|----------|----------|-------|----------------|
| CRITICAL | users.ts:45 | SQL injection via unsanitized input | Use parameterized queries |
| HIGH | auth.ts:23 | Missing rate limiting on login | Add rate limiter middleware |
| MEDIUM | users.ts:78 | No input validation | Add schema validation |
| LOW | auth.ts:12 | Magic number | Extract to named constant |

## Detailed Analysis

### CRITICAL: SQL Injection (users.ts:45)
[Detailed explanation with code example]

### HIGH: Missing Rate Limiting (auth.ts:23)
[Detailed explanation with recommendation]

## Recommendations
1. [Priority action items]
2. [Secondary improvements]

## Overall Assessment
[Summary judgment: PASS | NEEDS WORK | FAIL]

## Session
Session ID: `<id>` (for follow-up questions)

Workflow Example (ras-commander)

1. Write REVIEW.md

markdown

# Review Request: Remote Execution Security

## Objective
Security review of the PsExec-based remote execution module.

## Review Criteria
Rate findings: CRITICAL | HIGH | MEDIUM | LOW

Focus on:
- Command injection vulnerabilities
- Credential exposure
- Path traversal risks
- Session hijacking

## Code to Review

### File: ras_commander/remote/PsexecWorker.py
```python
[paste relevant code]

File: ras_commander/remote/Execution.py

python

[paste relevant code]

Context

•This module executes HEC-RAS remotely via PsExec
•Runs with elevated privileges on remote Windows machines
•Handles user credentials for authentication

Output Format

Write to FINDINGS.md with severity-rated findings and specific mitigations.

code


### 2. Execute Gemini

```bash
cd "C:/GH/ras-commander" && gemini -y "Read REVIEW.md, perform security review per criteria, write findings to FINDINGS.md"

3. Read FINDINGS.md

Review the findings, address issues, and continue development.

Environment Variables

bash

GEMINI_API_KEY=xxx         # Required (or use OAuth login)
GOOGLE_API_KEY=xxx         # Alternative (takes precedence)

Rate Limits

Limit	Value
Requests/minute	60
Requests/day	1,000

Session Management

•Session ID appears in Gemini output
•Use gemini --list-sessions to see available sessions
•Resume with gemini -r <id> "follow-up instruction"

Tips

•Paste actual code - Don't describe, include the real code in REVIEW.md
•Define severity levels - CRITICAL/HIGH/MEDIUM/LOW helps prioritization
•Specify output structure - Tell Gemini exactly what FINDINGS.md should contain
•Provide context - Domain, compliance requirements, constraints
•Ask focused questions - One review type per request gets better results

Decision Matrix: Gemini vs Codex

Task	Gemini	Codex
Code review / QAQC	Best	OK
Security audit	Best	OK
Implementation	OK	Best
Refactoring	OK	Best
Large codebase analysis	Best	OK
Documentation review	Best	OK
Extended thinking (20-30 min)	OK	Best

When to Escalate

Use Gemini for:

•Quick code reviews
•Documentation checks
•Large context analysis
•Security audits (initial scan)

Use Codex for:

•Complex implementation
•Extended thinking tasks
•Multi-file refactoring

Use specialized ras-commander agents for:

•HDF analysis -> hdf-analyst
•Geometry parsing -> geometry-parser
•USGS integration -> usgs-integrator

Cross-References

Agents (delegate when needed):

•code-oracle-gemini -- Delegate for large context Gemini analysis

Skills (related workflows):

•dev_invoke_codex-cli -- Alternative: Codex CLI for deep reasoning
•dev_invoke_kimi-cli -- Alternative: Kimi CLI for test generation
•qa_review_triple-model -- Uses this skill as one of three reviewers