feat: add issue body truncation to prevent GitHub API errors

Add truncation logic to handle GitHub's 65,000 character limit for issue
bodies. When command_output or parsed_output fields are very large, they
are now proportionally truncated before template rendering.

- Add truncation.py utility with proportional budget distribution
- Add constants for configurable max body length (default: 60,000)
- Integrate truncation in tac_sync_issues_cli and render_issue_bodies
- Add 24 unit tests for all truncation functions
- Support GITHUB_MAX_ISSUE_BODY_LENGTH env var for configuration

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: ChristopherJHart

github_ops_manager/configuration/cli.py

@@ -17,8 +17,10 @@
 from github_ops_manager.processing.yaml_processor import YAMLProcessor
 from github_ops_manager.schemas.default_issue import IssueModel, IssuesYAMLModel, PullRequestModel
 from github_ops_manager.synchronize.driver import run_process_issues_workflow
+from github_ops_manager.utils.constants import DEFAULT_MAX_ISSUE_BODY_LENGTH
 from github_ops_manager.utils.tac import find_issue_with_title
 from github_ops_manager.utils.templates import construct_jinja2_template_from_file, render_template_with_model
+from github_ops_manager.utils.truncation import truncate_test_case_outputs
 from github_ops_manager.utils.yaml import dump_yaml_to_file, load_test_case_definitions_from_directory, load_yaml_file
 
 load_dotenv()
@@ -77,6 +79,10 @@ def tac_sync_issues_cli(
     # can be constructed.
     template = construct_jinja2_template_from_file(Path(__file__).parent.parent / "templates" / "tac_issues_body.j2")
 
+    # Get max body length from environment variable or use default
+    max_body_length = int(os.getenv("GITHUB_MAX_ISSUE_BODY_LENGTH", str(DEFAULT_MAX_ISSUE_BODY_LENGTH)))
+    typer.echo(f"Using max issue body length: {max_body_length}")
+
     # Iterate through the test case definitions and ensure matching issues
     # exist in the YAML file.
     for test_case_definition in testing_as_code_test_case_definitions_model.test_cases:
@@ -100,10 +106,13 @@ def tac_sync_issues_cli(
             # script will have a control label called "script-already-created".
             # Additionally, a field named "generated_script_path" will be
             # populated with the path to the created test automation script.
+            #
+            # Truncate outputs if they would exceed the max body length
+            truncated_test_case = truncate_test_case_outputs(test_case_definition, max_body_length)
             new_issue = IssueModel(
                 title=test_case_definition.title,
                 body=render_template_with_model(
-                    model=test_case_definition,
+                    model=truncated_test_case,
                     template=template,
                 ),
                 labels=test_case_definition.labels,
@@ -124,8 +133,10 @@ def tac_sync_issues_cli(
             desired_issues_yaml_model.issues.append(new_issue)
         else:
             # Update the existing issue based upon the test case definition.
+            # Truncate outputs if they would exceed the max body length
+            truncated_test_case = truncate_test_case_outputs(test_case_definition, max_body_length)
             existing_issue.body = render_template_with_model(
-                model=test_case_definition,
+                model=truncated_test_case,
                 template=template,
             )
             existing_issue.labels = test_case_definition.labels

github_ops_manager/synchronize/issues.py

@@ -1,5 +1,6 @@
 """Contains synchronization logic for GitHub issues."""
 
+import os
 import time
 
 import jinja2
@@ -11,7 +12,9 @@
 from github_ops_manager.synchronize.models import SyncDecision
 from github_ops_manager.synchronize.results import AllIssueSynchronizationResults, IssueSynchronizationResult
 from github_ops_manager.synchronize.utils import compare_github_field, compare_label_sets
+from github_ops_manager.utils.constants import DEFAULT_MAX_ISSUE_BODY_LENGTH
 from github_ops_manager.utils.templates import construct_jinja2_template_from_file
+from github_ops_manager.utils.truncation import truncate_data_dict_outputs
 
 logger: structlog.stdlib.BoundLogger = structlog.get_logger(__name__)
 
@@ -140,8 +143,15 @@ async def render_issue_bodies(issues_yaml_model: IssuesYAMLModel) -> IssuesYAMLM
         logger.error("Encountered a syntax error with the provided issue template", issue_template=issues_yaml_model.issue_template, error=str(exc))
         raise
 
+    # Get max body length from environment variable or use default
+    max_body_length = int(os.getenv("GITHUB_MAX_ISSUE_BODY_LENGTH", str(DEFAULT_MAX_ISSUE_BODY_LENGTH)))
+
     for issue in issues_yaml_model.issues:
         if issue.data is not None:
+            # Truncate command outputs if present to fit within GitHub's body limit
+            if "commands" in issue.data:
+                issue.data = truncate_data_dict_outputs(issue.data, max_body_length)
+
             # Render with all issue fields available
             render_context = issue.model_dump()
             try:

github_ops_manager/utils/constants.py

@@ -23,3 +23,24 @@
 
 DEFAULT_RELEASE_NOTES_HEADER = "# Release Notes\n\nThis document tracks the new features, enhancements, and bug fixes for each release."
 """Default header expected in release notes file."""
+
+# Issue Body Truncation Constants
+# -------------------------------
+
+DEFAULT_MAX_ISSUE_BODY_LENGTH = 60000
+"""Default maximum length for issue bodies (leaves margin for GitHub's 65,536 limit)."""
+
+GITHUB_MAX_ISSUE_BODY_LENGTH = 65536
+"""GitHub's actual maximum issue body length."""
+
+TRUNCATION_SUFFIX = "\n... [truncated - {remaining} characters removed]"
+"""Suffix template appended to truncated content. Use .format(remaining=N) to fill in count."""
+
+TEMPLATE_OVERHEAD_PER_COMMAND = 500
+"""Estimated character overhead per command in the TAC issue template (markdown, code fences)."""
+
+BASE_TEMPLATE_OVERHEAD = 2000
+"""Estimated base overhead for non-command template content (headers, pass criteria, etc)."""
+
+MIN_OUTPUT_LENGTH = 500
+"""Minimum characters to preserve in truncated output fields for readability."""