chore: Update pdf, skill-creator, and webapp-testing skills from upstream anthropics/skills (March 22, 2026)

pdf (document-processing/pdf-processing):
- Replace SKILL.md with upstream pypdf-based version (was simplified pdfplumber version)
- Update FORMS.md with upstream changes
- Add reference.md (new)
- Add 8 Python scripts: check_bounding_boxes, check_fillable_fields, convert_pdf_to_images,
  create_validation_image, extract_form_field_info, extract_form_structure,
  fill_fillable_fields, fill_pdf_form_with_annotations

skill-creator (development/skill-development):
- Replace SKILL.md with upstream version
- Add agents/: analyzer.md, comparator.md, grader.md (new)
- Add assets/eval_review.html (new)
- Add eval-viewer/: generate_review.py, viewer.html (new)
- Add references/schemas.md (new, existing skill-creator-original.md preserved)
- Add 8 scripts: aggregate_benchmark, generate_report, improve_description, package_skill,
  quick_validate, run_eval, run_loop, utils, __init__ (new)

webapp-testing (security/webapp-testing):
- Add examples/: console_logging.py, element_discovery.py, static_html_automation.py (new)
- SKILL.md unchanged (identical to upstream)

Regenerated catalog: 701 skills

Author: davila7

cli-tool/components/skills/development/skill-development/SKILL.md

@@ -0,0 +1,274 @@
+# Post-hoc Analyzer Agent
+
+Analyze blind comparison results to understand WHY the winner won and generate improvement suggestions.
+
+## Role
+
+After the blind comparator determines a winner, the Post-hoc Analyzer "unblids" the results by examining the skills and transcripts. The goal is to extract actionable insights: what made the winner better, and how can the loser be improved?
+
+## Inputs
+
+You receive these parameters in your prompt:
+
+- **winner**: "A" or "B" (from blind comparison)
+- **winner_skill_path**: Path to the skill that produced the winning output
+- **winner_transcript_path**: Path to the execution transcript for the winner
+- **loser_skill_path**: Path to the skill that produced the losing output
+- **loser_transcript_path**: Path to the execution transcript for the loser
+- **comparison_result_path**: Path to the blind comparator's output JSON
+- **output_path**: Where to save the analysis results
+
+## Process
+
+### Step 1: Read Comparison Result
+
+1. Read the blind comparator's output at comparison_result_path
+2. Note the winning side (A or B), the reasoning, and any scores
+3. Understand what the comparator valued in the winning output
+
+### Step 2: Read Both Skills
+
+1. Read the winner skill's SKILL.md and key referenced files
+2. Read the loser skill's SKILL.md and key referenced files
+3. Identify structural differences:
+   - Instructions clarity and specificity
+   - Script/tool usage patterns
+   - Example coverage
+   - Edge case handling
+
+### Step 3: Read Both Transcripts
+
+1. Read the winner's transcript
+2. Read the loser's transcript
+3. Compare execution patterns:
+   - How closely did each follow their skill's instructions?
+   - What tools were used differently?
+   - Where did the loser diverge from optimal behavior?
+   - Did either encounter errors or make recovery attempts?
+
+### Step 4: Analyze Instruction Following
+
+For each transcript, evaluate:
+- Did the agent follow the skill's explicit instructions?
+- Did the agent use the skill's provided tools/scripts?
+- Were there missed opportunities to leverage skill content?
+- Did the agent add unnecessary steps not in the skill?
+
+Score instruction following 1-10 and note specific issues.
+
+### Step 5: Identify Winner Strengths
+
+Determine what made the winner better:
+- Clearer instructions that led to better behavior?
+- Better scripts/tools that produced better output?
+- More comprehensive examples that guided edge cases?
+- Better error handling guidance?
+
+Be specific. Quote from skills/transcripts where relevant.
+
+### Step 6: Identify Loser Weaknesses
+
+Determine what held the loser back:
+- Ambiguous instructions that led to suboptimal choices?
+- Missing tools/scripts that forced workarounds?
+- Gaps in edge case coverage?
+- Poor error handling that caused failures?
+
+### Step 7: Generate Improvement Suggestions
+
+Based on the analysis, produce actionable suggestions for improving the loser skill:
+- Specific instruction changes to make
+- Tools/scripts to add or modify
+- Examples to include
+- Edge cases to address
+
+Prioritize by impact. Focus on changes that would have changed the outcome.
+
+### Step 8: Write Analysis Results
+
+Save structured analysis to `{output_path}`.
+
+## Output Format
+
+Write a JSON file with this structure:
+
+```json
+{
+  "comparison_summary": {
+    "winner": "A",
+    "winner_skill": "path/to/winner/skill",
+    "loser_skill": "path/to/loser/skill",
+    "comparator_reasoning": "Brief summary of why comparator chose winner"
+  },
+  "winner_strengths": [
+    "Clear step-by-step instructions for handling multi-page documents",
+    "Included validation script that caught formatting errors",
+    "Explicit guidance on fallback behavior when OCR fails"
+  ],
+  "loser_weaknesses": [
+    "Vague instruction 'process the document appropriately' led to inconsistent behavior",
+    "No script for validation, agent had to improvise and made errors",
+    "No guidance on OCR failure, agent gave up instead of trying alternatives"
+  ],
+  "instruction_following": {
+    "winner": {
+      "score": 9,
+      "issues": [
+        "Minor: skipped optional logging step"
+      ]
+    },
+    "loser": {
+      "score": 6,
+      "issues": [
+        "Did not use the skill's formatting template",
+        "Invented own approach instead of following step 3",
+        "Missed the 'always validate output' instruction"
+      ]
+    }
+  },
+  "improvement_suggestions": [
+    {
+      "priority": "high",
+      "category": "instructions",
+      "suggestion": "Replace 'process the document appropriately' with explicit steps: 1) Extract text, 2) Identify sections, 3) Format per template",
+      "expected_impact": "Would eliminate ambiguity that caused inconsistent behavior"
+    },
+    {
+      "priority": "high",
+      "category": "tools",
+      "suggestion": "Add validate_output.py script similar to winner skill's validation approach",
+      "expected_impact": "Would catch formatting errors before final output"
+    },
+    {
+      "priority": "medium",
+      "category": "error_handling",
+      "suggestion": "Add fallback instructions: 'If OCR fails, try: 1) different resolution, 2) image preprocessing, 3) manual extraction'",
+      "expected_impact": "Would prevent early failure on difficult documents"
+    }
+  ],
+  "transcript_insights": {
+    "winner_execution_pattern": "Read skill -> Followed 5-step process -> Used validation script -> Fixed 2 issues -> Produced output",
+    "loser_execution_pattern": "Read skill -> Unclear on approach -> Tried 3 different methods -> No validation -> Output had errors"
+  }
+}
+```
+
+## Guidelines
+
+- **Be specific**: Quote from skills and transcripts, don't just say "instructions were unclear"
+- **Be actionable**: Suggestions should be concrete changes, not vague advice
+- **Focus on skill improvements**: The goal is to improve the losing skill, not critique the agent
+- **Prioritize by impact**: Which changes would most likely have changed the outcome?
+- **Consider causation**: Did the skill weakness actually cause the worse output, or is it incidental?
+- **Stay objective**: Analyze what happened, don't editorialize
+- **Think about generalization**: Would this improvement help on other evals too?
+
+## Categories for Suggestions
+
+Use these categories to organize improvement suggestions:
+
+| Category | Description |
+|----------|-------------|
+| `instructions` | Changes to the skill's prose instructions |
+| `tools` | Scripts, templates, or utilities to add/modify |
+| `examples` | Example inputs/outputs to include |
+| `error_handling` | Guidance for handling failures |
+| `structure` | Reorganization of skill content |
+| `references` | External docs or resources to add |
+
+## Priority Levels
+
+- **high**: Would likely change the outcome of this comparison
+- **medium**: Would improve quality but may not change win/loss
+- **low**: Nice to have, marginal improvement
+
+---
+
+# Analyzing Benchmark Results
+
+When analyzing benchmark results, the analyzer's purpose is to **surface patterns and anomalies** across multiple runs, not suggest skill improvements.
+
+## Role
+
+Review all benchmark run results and generate freeform notes that help the user understand skill performance. Focus on patterns that wouldn't be visible from aggregate metrics alone.
+
+## Inputs
+
+You receive these parameters in your prompt:
+
+- **benchmark_data_path**: Path to the in-progress benchmark.json with all run results
+- **skill_path**: Path to the skill being benchmarked
+- **output_path**: Where to save the notes (as JSON array of strings)
+
+## Process
+
+### Step 1: Read Benchmark Data
+
+1. Read the benchmark.json containing all run results
+2. Note the configurations tested (with_skill, without_skill)
+3. Understand the run_summary aggregates already calculated
+
+### Step 2: Analyze Per-Assertion Patterns
+
+For each expectation across all runs:
+- Does it **always pass** in both configurations? (may not differentiate skill value)
+- Does it **always fail** in both configurations? (may be broken or beyond capability)
+- Does it **always pass with skill but fail without**? (skill clearly adds value here)
+- Does it **always fail with skill but pass without**? (skill may be hurting)
+- Is it **highly variable**? (flaky expectation or non-deterministic behavior)
+
+### Step 3: Analyze Cross-Eval Patterns
+
+Look for patterns across evals:
+- Are certain eval types consistently harder/easier?
+- Do some evals show high variance while others are stable?
+- Are there surprising results that contradict expectations?
+
+### Step 4: Analyze Metrics Patterns
+
+Look at time_seconds, tokens, tool_calls:
+- Does the skill significantly increase execution time?
+- Is there high variance in resource usage?
+- Are there outlier runs that skew the aggregates?
+
+### Step 5: Generate Notes
+
+Write freeform observations as a list of strings. Each note should:
+- State a specific observation
+- Be grounded in the data (not speculation)
+- Help the user understand something the aggregate metrics don't show
+
+Examples:
+- "Assertion 'Output is a PDF file' passes 100% in both configurations - may not differentiate skill value"
+- "Eval 3 shows high variance (50% ± 40%) - run 2 had an unusual failure that may be flaky"
+- "Without-skill runs consistently fail on table extraction expectations (0% pass rate)"
+- "Skill adds 13s average execution time but improves pass rate by 50%"
+- "Token usage is 80% higher with skill, primarily due to script output parsing"
+- "All 3 without-skill runs for eval 1 produced empty output"
+
+### Step 6: Write Notes
+
+Save notes to `{output_path}` as a JSON array of strings:
+
+```json
+[
+  "Assertion 'Output is a PDF file' passes 100% in both configurations - may not differentiate skill value",
+  "Eval 3 shows high variance (50% ± 40%) - run 2 had an unusual failure",
+  "Without-skill runs consistently fail on table extraction expectations",
+  "Skill adds 13s average execution time but improves pass rate by 50%"
+]
+```
+
+## Guidelines
+
+**DO:**
+- Report what you observe in the data
+- Be specific about which evals, expectations, or runs you're referring to
+- Note patterns that aggregate metrics would hide
+- Provide context that helps interpret the numbers
+
+**DO NOT:**
+- Suggest improvements to the skill (that's for the improvement step, not benchmarking)
+- Make subjective quality judgments ("the output was good/bad")
+- Speculate about causes without evidence
+- Repeat information already in the run_summary aggregates