Two MCP tools blew the per-response token cap when run against a real
medium-sized cluster (Bingham Memorial, ~1500 patterns in Internal-PT,
20 route filters with hundreds of member rules each):
route_devices_using_css("Internal-CSS") -> 103,590 chars
route_filters() -> 304,639 chars
Both responses are now compact-by-default with opt-in detail:
route_filters(include_members=False, default):
- returns name, clause, dial_plan, and member_count per filter
- 304,639 -> 17,354 chars (94% reduction)
- member_count is the audit-relevant signal anyway: filters with
100+ rules are complex; the count tells you that without paying
for the full rule listing
- include_members=True scopes detail to a single named filter
(BLK-ALWAYS-RF with 432 rules: 40K chars; tractable per-filter)
route_devices_using_css(max_per_category=50, default):
- each category returns at most max_per_category rows
- truncated: bool flag set when underlying count exceeds the cap
- 103,590 -> 13,855 chars (87% reduction)
- implementation uses SELECT FIRST max+1, so no extra COUNT query
per category — single round-trip with accurate truncation flag
- LLM can drill in via higher max_per_category or axl_sql when
truncated=true
Both changes are backward-compatible defaults; existing callers continue
to work and just get smaller, structured responses.
mcp-cucm-axl
Read-only MCP server for Cisco Unified CM 15 AXL — built for LLM-driven cluster auditing, with a particular focus on the Route Plan Report: partitions, calling search spaces, route patterns, translation patterns, called/calling party transformations, and digit-discard instructions.
Why this exists
CUCM's admin UI is great for one-config-at-a-time work but painful for audit/discovery questions like:
- "Which translation patterns rewrite the calling party number, and why?"
- "Which CSSs include the
Internal_PTpartition, in what order?" - "Show me every route pattern targeting the SIP trunk to the carrier."
- "Are there partitions defined but unreachable from any CSS?"
This server gives an LLM SQL access to CUCM's Informix data dictionary,
plus focused tools that bake in the right joins for routing-audit work.
Pair it with the sibling mcp-cisco-docs server and the LLM
gets vendor documentation alongside live cluster state — answering
"is our config consistent with Cisco's recommended baseline?" in a single
conversation.
Read-only by structural guarantee
The server never registers AXL write methods. There is no
executeSQLUpdate, no add*/update*/remove*/apply*/reset*/
restart* tool. Read-only is enforced by absence of write operations,
not by runtime sanitization. Defense-in-depth: SQL queries are also
client-side validated to begin with SELECT or WITH.
Setup
1. Configure environment
Edit .env (already gitignored):
AXL_URL=https://cucm-pub:8443/axl
AXL_USER=AxlUser
AXL_PASS=...
AXL_VERIFY_TLS=false # CUCM ships self-signed certs; default off
AXL_CACHE_TTL=3600 # 1 hour; 0 disables caching
AXL_WSDL_PATH= # optional explicit WSDL location
CISCO_DOCS_INDEX_PATH= # optional override for prompt enrichment
2. Bootstrap the AXL WSDL
Download the Cisco AXL Toolkit from your CUCM admin UI:
Application → Plugins → Find → "Cisco AXL Toolkit" → Download
Drop the resulting axlsqltoolkit.zip into the project directory. On first
launch, the server auto-extracts schema/15.0/ into ~/.cache/mcp-cucm-axl/wsdl/15.0/.
The zip is gitignored (Cisco-licensed; not redistributable).
Alternatives (in resolution order):
# A: explicit zip elsewhere
export AXL_WSDL_ZIP=/path/to/axlsqltoolkit.zip
# B: explicit WSDL file
export AXL_WSDL_PATH=/path/to/schema/15.0/AXLAPI.wsdl
# C: pre-populated cache directory
mkdir -p ~/.cache/mcp-cucm-axl/wsdl/15.0/
cp /path/to/schema/15.0/* ~/.cache/mcp-cucm-axl/wsdl/15.0/
3. Install + run
uv sync
uv run mcp-cucm-axl
Or via the bundled .mcp.json, automatically registered when Claude Code
opens this directory.
Tool surface
Foundational
| Tool | Purpose |
|---|---|
axl_version() |
Cluster version sanity check |
axl_sql(query) |
Execute a SELECT against Informix data dictionary |
axl_list_tables(pattern=None) |
Discover Informix tables |
axl_describe_table(name) |
Column metadata for one table |
cache_stats(), cache_clear(pattern=None) |
Cache plumbing |
Route plan
| Tool | Purpose |
|---|---|
route_partitions() |
All partitions with pattern + CSS-member counts |
route_calling_search_spaces(name=None) |
CSS list with ordered partitions |
route_patterns(kind=None, partition=None, filter=None) |
Route Plan Report — patterns + transformations |
route_inspect_pattern(pattern, partition=None) |
Deep dive: transforms, route filter, reachable-from CSS, full destination chain (route list → groups → gateways) |
route_lists_and_groups(name=None) |
Route list → route group → gateway chain (annotates Local Route Group placeholders) |
route_translation_chain(number, css_name=None) |
Wildcard-aware pattern matcher: evaluates X / ! / [0-9] / @ / \+ against the number and returns matches sorted by specificity |
route_digit_discard_instructions() |
DDI catalog |
route_device_pool_route_groups(device_pool_name=None) |
How each device pool resolves Local Route Group placeholders to actual gateway-bearing groups |
route_devices_using_css(css_name) |
Impact analysis: every reference to a CSS across line CFA/CFB/CFNA/CFUR/translation/MWI/shared, device-level CSSs, voicemail pilots, route lists |
route_filters(name=None) |
Route filter clauses + member rules (composed with @-pattern routes) |
Prompts
Schema-grounded conversation seeds. They pull relevant chunks from the
sibling cisco-docs index and embed them inline:
route_plan_overview— fresh audit conversation seedinvestigate_pattern(pattern, partition=None)— deep-dive a specific patternaudit_routing(focus="full")— comprehensive audit walkthroughcucm_sql_help(question)— catch-all for arbitrary SQL questions
Cache
Responses are cached in SQLite at ~/.cache/mcp-cucm-axl/responses/axl_responses.sqlite.
Cache survives restarts. Clear with cache_clear() after a known config change.
Notes
route_translation_chaindoes literal/prefix matching only. CUCM's actual matcher evaluates wildcards (X,!,[0-9], etc.) and selects the longest match. Treat results as "patterns to investigate" rather than "definitive route."- Pattern type codes (
tkpatternusage) used byroute_patterns(kind=...)are stable across CUCM versions but enumerated against thetypepatternusagetable at query time, so any cluster-specific custom types still work.