Make FASTMCP_SHOW_SERVER_BANNER apply to all server startup methods

[jlowin]

The FASTMCP_SHOW_CLI_BANNER setting only worked when using fastmcp run. When running servers directly via python server.py (calling mcp.run()), the env var was ignored.

This PR renames the setting to FASTMCP_SHOW_SERVER_BANNER and makes run() / run_async() respect it. The show_banner parameter now defaults to None, which resolves to the setting value.

# Now works in all cases:
# FASTMCP_SHOW_SERVER_BANNER=false python server.py
# FASTMCP_SHOW_SERVER_BANNER=false fastmcp run server.py

# Explicit override still works:
mcp.run(show_banner=False)

[coderabbitai]

Walkthrough

This pull request renames the environment variable and settings configuration field from show_cli_banner to show_server_banner, reflecting that banner suppression now applies across all server startup methods rather than just CLI invocations. The server's run() and run_async() methods are updated to accept an optional show_banner parameter that defaults to the global setting when not explicitly provided. Supporting updates are made to the CLI module and documentation to align with this terminology and behavior change.

Possibly related PRs

• Update CLI banner with FastMCP 3.0 notice #2766: Modifies server banner logging implementation and how run/run_async methods invoke the banner display logic.
• Update CLI banner with FastMCP 3.0 notice #2765: Alters the log_server_banner function and adjusts how server run methods call it, directly intersecting with banner handling changes.

Pre-merge checks and finishing touches

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Description check	⚠️ Warning	The description explains the problem, solution, and usage examples clearly, but lacks the required Contributors Checklist items marked, which are mandatory per the template.	Complete all checklist items from the Contributors Checklist section, including marking which issue this closes and confirming testing and documentation updates were performed.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and accurately summarizes the main objective: renaming the setting and making it apply universally to all server startup methods, not just the CLI.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch feat/show-server-banner-setting

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[coderabbitai]

Actionable comments posted: 1

📜 Review details

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📥 Commits

Reviewing files that changed from the base of the PR and between ef84f84 and a763058.

⛔ Files ignored due to path filters (2)

• tests/cli/test_cli.py is excluded by none and included by none
• tests/server/test_server.py is excluded by none and included by none

📒 Files selected for processing (4)

• docs/development/upgrade-guide.mdx
• src/fastmcp/cli/cli.py
• src/fastmcp/server/server.py
• src/fastmcp/settings.py

🧰 Additional context used

📓 Path-based instructions (4)

src/fastmcp/**/*.py

📄 CodeRabbit inference engine (AGENTS.md)

src/fastmcp/**/*.py: Python ≥ 3.10 with full type annotations required
Prioritize readable, understandable code - clarity over cleverness. Avoid obfuscated or confusing patterns even if shorter
Follow existing patterns and maintain consistency in code implementation
Be intentional about re-exports - don't blindly re-export everything to parent namespaces. Core types defining a module's purpose should be exported. Specialized features can live in submodules. Only re-export to fastmcp.* for most fundamental types
Never use bare except - be specific with exception types

Files:

• src/fastmcp/server/server.py
• src/fastmcp/settings.py
• src/fastmcp/cli/cli.py

docs/**/*.mdx

📄 CodeRabbit inference engine (docs/.cursor/rules/mintlify.mdc)

docs/**/*.mdx: Use clear, direct language appropriate for technical audiences
Write in second person ('you') for instructions and procedures in MDX documentation
Use active voice over passive voice in MDX technical documentation
Employ present tense for current states and future tense for outcomes in MDX documentation
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Files:

• docs/development/upgrade-guide.mdx

docs/**/*.{md,mdx,json}

📄 CodeRabbit inference engine (AGENTS.md)

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Files:

• docs/development/upgrade-guide.mdx

docs/**/*.{md,mdx}

📄 CodeRabbit inference engine (AGENTS.md)

docs/**/*.{md,mdx}: Code examples in documentation must explain before showing code and make blocks fully runnable (include imports)
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Never use 'This isn't...' or 'not just...' constructions in writing - state what something IS directly. Avoid defensive writing patterns

Files:

• docs/development/upgrade-guide.mdx

🧠 Learnings (2)

📚 Learning: 2025-12-25T15:53:07.646Z

Learnt from: CR
Repo: jlowin/fastmcp PR: 0
File: AGENTS.md:0-0
Timestamp: 2025-12-25T15:53:07.646Z
Learning: Applies to tests/**/*.py : Pass FastMCP servers directly to clients for testing without network complexity; only use HTTP transport when explicitly testing network features

Applied to files:

• src/fastmcp/server/server.py

📚 Learning: 2025-12-25T15:53:07.646Z

Learnt from: CR
Repo: jlowin/fastmcp PR: 0
File: AGENTS.md:0-0
Timestamp: 2025-12-25T15:53:07.646Z
Learning: Applies to src/fastmcp/**/*.py : Python ≥ 3.10 with full type annotations required

Applied to files:

• docs/development/upgrade-guide.mdx

🧬 Code graph analysis (2)

src/fastmcp/server/server.py (2)

src/fastmcp/server/low_level.py (2)

• fastmcp (45-50)
• fastmcp (146-151)

src/fastmcp/server/context.py (1)

• fastmcp (169-174)

src/fastmcp/cli/cli.py (3)

src/fastmcp/server/low_level.py (2)

• fastmcp (45-50)
• fastmcp (146-151)

src/fastmcp/server/context.py (1)

• fastmcp (169-174)

src/fastmcp/server/server.py (1)

• settings (408-416)

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• GitHub Check: Run tests: Python 3.10 on windows-latest
• GitHub Check: Run tests: Python 3.10 on ubuntu-latest
• GitHub Check: Run tests: Python 3.13 on ubuntu-latest
• GitHub Check: Run tests with lowest-direct dependencies

🔇 Additional comments (4)

src/fastmcp/settings.py (1)

323-335: LGTM!

The field rename from show_cli_banner to show_server_banner accurately reflects the expanded scope. The description clearly documents the override mechanisms (CLI flag and server.run() parameter) and references the correct environment variable.

src/fastmcp/server/server.py (2)

556-588: LGTM! Clean defaulting pattern.

The signature change to show_banner: bool | None = None with defaulting logic (lines 569-570) correctly implements the PR's intent. When None, it reads the global FASTMCP_SHOW_SERVER_BANNER setting; when explicitly provided, it honors the caller's choice. This preserves backward compatibility while extending control to programmatic server startup.

---

590-611: Consistent with run_async().

The run() method signature and docstring match run_async(), ensuring a consistent API. The parameter is correctly passed through to run_async() where the defaulting logic resides.

src/fastmcp/cli/cli.py (1)

426-429: Correct CLI flag and setting integration.

The logic properly prioritizes the --no-banner CLI flag over the global show_server_banner setting, and correctly handles the inverted semantics (no_banner vs show_banner). When the flag isn't provided, it defaults to the global setting's inverted value.

[coderabbitai]

⚠️ Potential issue | 🟡 Minor

Clarify the banner behavior description.

Line 189 states "The banner is now suppressed when running python server.py directly," which is imprecise. The setting controls whether the banner is shown or hidden—it's not necessarily suppressed. When FASTMCP_SHOW_SERVER_BANNER=true (the default), the banner displays for all startup methods including direct Python runs.

Consider revising to something like: "This change reflects that the setting now controls banner display for all server startup methods (both CLI and direct Python execution), not just CLI invocations."

🔎 Suggested revision

-The environment variable for controlling the server banner has been renamed:
-
-- **Before:** `FASTMCP_SHOW_CLI_BANNER`
-- **After:** `FASTMCP_SHOW_SERVER_BANNER`
-
-This change reflects that the setting now applies to all server startup methods, not just the CLI. The banner is now suppressed when running `python server.py` directly, not just when using `fastmcp run`.
+The environment variable for controlling the server banner has been renamed:
+
+- **Before:** `FASTMCP_SHOW_CLI_BANNER`
+- **After:** `FASTMCP_SHOW_SERVER_BANNER`
+
+This change reflects that the setting now controls banner display for all server startup methods (both CLI and direct Python execution), not just CLI invocations. Set `FASTMCP_SHOW_SERVER_BANNER=false` to suppress the banner across all startup methods.

📝 Committable suggestion

‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.

Suggested change

	### Server Banner Environment Variable Renamed
	The environment variable for controlling the server banner has been renamed:
	- **Before:** `FASTMCP_SHOW_CLI_BANNER`
	- **After:** `FASTMCP_SHOW_SERVER_BANNER`
	This change reflects that the setting now applies to all server startup methods, not just the CLI. The banner is now suppressed when running `python server.py` directly, not just when using `fastmcp run`.
	### Server Banner Environment Variable Renamed
	The environment variable for controlling the server banner has been renamed:
	- **Before:** `FASTMCP_SHOW_CLI_BANNER`
	- **After:** `FASTMCP_SHOW_SERVER_BANNER`
	This change reflects that the setting now controls banner display for all server startup methods (both CLI and direct Python execution), not just CLI invocations. Set `FASTMCP_SHOW_SERVER_BANNER=false` to suppress the banner across all startup methods.

[marvin-context-protocol]

Test Failure Analysis

Summary: The integration test is failing due to GitHub API rate limiting (HTTP 429), not due to the changes in this PR.

Root Cause: The test is hitting the GitHub Copilot MCP API at and receiving a 429 Too Many Requests error. The test times out after 30 seconds waiting for a response that never comes because the API request is rate limited.

Suggested Solution: This is a transient infrastructure issue, not a code issue. The PR changes only rename the banner setting from FASTMCP_SHOW_CLI_BANNER to FASTMCP_SHOW_SERVER_BANNER and make the show_banner parameter work with mcp.run(). These changes are unrelated to the GitHub API integration tests.

Recommendation: Re-run the integration tests. If rate limiting persists, consider:

1. Adding retry logic with exponential backoff for GitHub API calls in integration tests
2. Implementing test rate limit detection and automatic skip/xfail marking
3. Reviewing GitHub API token permissions and rate limits

Detailed Analysis

The test failure occurs in tests/integration_tests/test_github_mcp_remote.py::TestGithubMCPRemote::test_call_tool_list_commits.

Error Details:

httpx.HTTPStatusError: Client error '429 Too Many Requests' for url 'https://api.githubcopilot.com/mcp/'
For more information check: https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/429

Test Timeout:

• Test has a 30-second timeout
• The HTTP request hangs indefinitely due to rate limiting
• Test eventually times out: Failed: Timeout (>30.0s) from pytest-timeout.

Why This is Unrelated to PR Changes:
This PR modifies:

• src/fastmcp/settings.py: Renames show_cli_banner to show_server_banner
• src/fastmcp/server/server.py: Makes show_banner parameter default to None and read from settings
• src/fastmcp/cli/cli.py: Updates reference to renamed setting

None of these changes affect:

• HTTP client behavior
• API authentication
• Network requests to GitHub
• Integration test logic

Related Files

• Test file: tests/integration_tests/test_github_mcp_remote.py:99-124 - The failing test
• Transport: fastmcp/client/client.py - Client HTTP transport handling
• GitHub MCP URL: https://api.githubcopilot.com/mcp/ - The rate-limited endpoint

The test authenticates using FASTMCP_GITHUB_TOKEN and calls the list_commits tool on the GitHub MCP server. All other integration tests in this suite passed (13/14), suggesting this is a transient rate limit issue rather than a systematic problem.

[marvin-context-protocol]

Test Failure Analysis

Summary: The integration test test_call_tool_list_commits is failing due to GitHub API rate limiting (HTTP 429), not due to the changes in this PR.

Root Cause: The test is hitting the GitHub Copilot MCP API at https://api.githubcopilot.com/mcp/ and receiving a 429 Too Many Requests error. The test times out after 30 seconds waiting for a response that never comes because the API request is rate limited.

Suggested Solution: This is a transient infrastructure issue, not a code issue. The PR changes only rename the banner setting from FASTMCP_SHOW_CLI_BANNER to FASTMCP_SHOW_SERVER_BANNER and make the show_banner parameter work with mcp.run(). These changes are unrelated to the GitHub API integration tests.

Recommendation: Re-run the integration tests. If rate limiting persists, consider:

1. Adding retry logic with exponential backoff for GitHub API calls in integration tests
2. Implementing test rate limit detection and automatic skip/xfail marking
3. Reviewing GitHub API token permissions and rate limits

Detailed Analysis

The test failure occurs in tests/integration_tests/test_github_mcp_remote.py::TestGithubMCPRemote::test_call_tool_list_commits.

Error Details:

httpx.HTTPStatusError: Client error '429 Too Many Requests' for url 'https://api.githubcopilot.com/mcp/'
For more information check: https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/429

Test Timeout:

• Test has a 30-second timeout
• The HTTP request hangs indefinitely due to rate limiting
• Test eventually times out: Failed: Timeout (>30.0s) from pytest-timeout.

Why This is Unrelated to PR Changes:
This PR modifies:

• src/fastmcp/settings.py: Renames show_cli_banner to show_server_banner
• src/fastmcp/server/server.py: Makes show_banner parameter default to None and read from settings
• src/fastmcp/cli/cli.py: Updates reference to renamed setting

None of these changes affect:

• HTTP client behavior
• API authentication
• Network requests to GitHub
• Integration test logic

Related Files

• Test file: tests/integration_tests/test_github_mcp_remote.py:99-124 - The failing test
• Transport: fastmcp/client/client.py - Client HTTP transport handling
• GitHub MCP URL: https://api.githubcopilot.com/mcp/ - The rate-limited endpoint

The test authenticates using FASTMCP_GITHUB_TOKEN and calls the list_commits tool on the GitHub MCP server. All other integration tests in this suite passed (13/14), suggesting this is a transient rate limit issue rather than a systematic problem.