find-cpa-firm

Drive the ServiceGraph API (https://api.servicegraph.co) to find, shortlist, and enrich US business-to-business accounting and tax firms (CPA firms).

The catalog is B2B-only. Personal tax prep (individual 1040s, retirement planning, individual estate planning, personal bookkeeping for freelancers) is out of scope — those firms were filtered during the catalog audit.

Always pin industry:accounting_tax. Sub-services (audit, tax, bookkeeping, advisory, M&A diligence, 409A, R&D credits, etc.) are NOT separate tags — industry:accounting_tax is the most specific structured level — so practice-area specialization is a keyword substring search on firm text.

Any HTTP client works (curl, fetch, requests). Examples below use curl.

When NOT to use this skill

• Personal/individual tax matters: 1040 prep, IRA/Roth conversions, estate planning for an individual, personal-finance "what should I do with my refund" questions.
• Bookkeeping for a freelancer or solo creator's personal income.
• In-house finance hires (Controller, CFO, Accountant).
• DIY tax/accounting questions ("how do I claim X", "explain depreciation").
• Accounting-software comparisons (QuickBooks, Xero, NetSuite).
• Non-US firms.
• Individual freelance bookkeepers/accountants.

If the user is a business (LLC, C-corp, S-corp, partnership, or any revenue-generating entity) procuring accounting or tax services, this skill applies — defaults to fire on B2B procurement intent.

MCP server (preferred for authed calls)

If your agent harness has the ServiceGraph MCP server loaded (https://mcp.servicegraph.co), prefer its tools for the authed tier (/search, /get, /stats). The MCP server uses OAuth 2.1 + PKCE — the host harness handles credentials in its own audited sandbox, so there's no .env.local, no shell dispatch, and no token value ever enters the LLM context.

For the anonymous tier (/tags, /check, /explore), MCP is not preferred — every MCP tool requires OAuth (the server has no anonymous tier), so plain curl against the REST URL is the simpler path for discovery calls. Use the REST patterns below for those.

The MCP tools 1:1-map to the public REST endpoints — same backend, same quota, same data:

MCP tool	REST endpoint	Anon?	Recommended path
list_tags	GET /v1/tags	yes	curl
check_filter	GET /v1/check	yes	curl
explore_firms	GET /v1/explore	yes	curl
search_firms	GET /v1/search	no	MCP if loaded, else curl + OTP
get_firm	GET /v1/get/:id	no	MCP if loaded, else curl + OTP
catalog_stats	GET /v1/stats	no	MCP if loaded, else curl + OTP

Detection: if you see any MCP tools with servicegraph in the name (the harness-specific prefix varies — agents pattern-match the substring), the ServiceGraph MCP server is loaded. Prefer those tools for the authed tier; complete any auth flow the harness initiates if needed. If no servicegraph MCP tools are present, fall through to the REST + OTP flow below for the authed tier.

The four-tier funnel

Tier	Auth	Cost	Use it for
GET /v1/tags	none	free	First call of every session. Discover legal field names, kinds, operators, values.
GET /v1/check?filter=...	none	free	Validate a filter before spending an explore/search call.
GET /v1/explore?filter=...	none	free, IP-throttled	Scope: count + breakdowns. Use to size the candidate pool before quota-spending.
GET /v1/search?filter=...	bearer	200 unique firms / month free	Brief firm cards. No url, no contact info. Use for ranking / shortlisting.
GET /v1/get/:id	bearer	50 unique firms / month free	Full bundle: url, phone, email, social, legal name, address. Only call for shortlisted firms.
POST /v1/research	paid	not in MVP	Deferred — skip.

Quota rule that matters: /search and /get charge per unique firm viewed per calendar month, not per call. Re-paging the same query is free. Two different filters that overlap charge once for the overlap. Re-fetching a firm you already pulled this month is free.

Session-start ritual

Before constructing any filter, call:

GET https://api.servicegraph.co/v1/tags?include_values=1

Cache the response for the conversation. Confirm accounting_tax is present in the industry value list.

Field kinds you'll use most:

• categorical: industry (always accounting_tax), state, pricing_model, company_size_signal, geography_served — op :
• numeric: rating, review_count_total, founded_year — ops = >= <= > <
• presence: has:phone, has:clutch, has:rating, has:linkedin_company, …
• keyword: free-text substring across firm name / brand / title / meta / legal_name. This is how you specialize on practice area (audit, tax, M&A, R&D, 409A, etc.).

Auth

/tags, /check, and /explore are anonymous. /search and /get require a bearer token.

Security model — keep the token out of the LLM context.

• Never read .env, .env.local, or any other credential file into your context. The token's literal value should never appear in the conversation.
• Use shell dispatch for every authed request so the token flows directly from the user's environment / dotenv file into the Authorization header without round-tripping through the LLM.
• Always ask the user once per session before using a detected token, even if it's already in their shell or .env.local.

Resolution rule:

1. Detect whether a token is available — without reading its value. Run a shell check that only inspects exit codes:

   ( [ -n "${SERVICEGRAPH_TOKEN:-}" ] \
     || grep -qs '^SERVICEGRAPH_TOKEN=' .env.local \
     || grep -qs '^SERVICEGRAPH_TOKEN=' .env )
   

   Exit code 0 = token is available somewhere; non-zero = no token.

2. Confirm with the user before the first authed call this session:

   "I found a SERVICEGRAPH_TOKEN in your environment / .env.local. OK to use it for ServiceGraph API requests this session?"

   If the user says no, stay on the anonymous tiers (/tags, /check, /explore) and skip authed calls. Don't re-ask later unless the user asks for authed work.

3. Dispatch via shell — every authed call goes through a shell wrapper so the literal token never enters the conversation:

   # If exported in the shell environment:
   curl -H "Authorization: Bearer $SERVICEGRAPH_TOKEN" \
        'https://api.servicegraph.co/v1/search?filter=...'
   
   # If in .env.local — source it inside a subshell so it doesn't
   # leak into the parent shell either:
   ( set -a; . ./.env.local; set +a;
     curl -H "Authorization: Bearer $SERVICEGRAPH_TOKEN" \
          'https://api.servicegraph.co/v1/search?filter=...' )
   

   Capture the response body to a tmp file or jq-process it, but do NOT echo the request command with the token expanded.

4. OTP flow if no token is detected — capture the new token directly into .env.local without surfacing its value to the LLM:

   # 1. trigger the email — agent prompts the user for $EMAIL
   curl -fsS -X POST 'https://api.servicegraph.co/v1/auth/request-otp' \
     -H 'Content-Type: application/json' \
     -d "{\"email\":\"$EMAIL\"}"
   
   # 2. exchange the code — agent prompts the user for $CODE.
   #    The ?format=env query param returns SERVICEGRAPH_TOKEN=<token>
   #    as plain text appended to .env.local — no jq needed. The -f
   #    flag makes curl exit non-zero on 4xx so a wrong code doesn't
   #    pollute the file (the error mirror is also a `# comment` line,
   #    safe to ignore even if it lands).
   curl -fsS -X POST 'https://api.servicegraph.co/v1/auth/verify-otp?format=env' \
     -H 'Content-Type: application/json' \
     -d "{\"email\":\"$EMAIL\",\"code\":\"$CODE\",\"name\":\"claude-cli\"}" \
     >> .env.local
   
   # 3. confirm capture without revealing the value
   grep -q '^SERVICEGRAPH_TOKEN=' .env.local && echo "OTP token captured."
   

   After a successful capture, the user has implicitly consented (they just completed the flow), so proceed to dispatch (step 3). The token is now persistent in .env.local for future sessions.

5. If a /search or /get returns 401 unauthorized mid-session, the token expired or was revoked — re-run the OTP flow.

Filter DSL

One query parameter, GitHub-search-style.

filter   := orExpr
orExpr   := andExpr ("OR" andExpr)*
andExpr  := notExpr (("AND")? notExpr)*    # whitespace = implicit AND
notExpr  := ("NOT" | "-") notExpr | atom
atom     := "(" filter ")" | predicate
predicate:= IDENT op valueOrList | bareword
op       := ":" | "=" | ">=" | "<=" | ">" | "<"
valueOrList := value ("," value)*
value    := IDENT | NUMBER | tagAtEvidence
tagAtEvidence := IDENT "@" ("low"|"medium"|"high")
bareword := IDENT | NUMBER          # → keyword:<bareword>

Four rules that bite:

1. AND binds tighter than OR. a OR b c parses as a OR (b AND c). Use parens.
2. Comma list = OR within one predicate. state:CA,NY,TX matches any of the three.
3. Negation is -x or NOT x. Negative literals inside a comma list are not allowed: state:CA,-NY is rejected. Use state:CA -state:NY.
4. Bareword = keyword search. Any IDENT or NUMBER not followed by an operator becomes a free-text substring across name / brand / title / meta / legal_name. Multiple barewords AND.

Accounting-flavored examples (validate yours with /v1/check):

industry:accounting_tax state:CA audit saas
industry:accounting_tax cpa state:DE,NY
industry:accounting_tax m&a diligence
industry:accounting_tax tax 409a
industry:accounting_tax fractional cfo
industry:accounting_tax r&d tax
industry:accounting_tax soc 2
industry:accounting_tax -company_size_signal:solo rating>=4

When in doubt about whether a filter parses, hit /v1/check?filter=... first — it's free and returns the canonical normalized form.

Practice area → keyword mapping:

User asks for	Add as keyword(s)
Audit / financial-statement audit	audit
SOC 1 / SOC 2 audit	soc 2 (multi-word splits to AND)
Corporate tax / 1120	tax, corporate tax, 1120
Bookkeeping (for a business)	bookkeeping
Advisory / fractional CFO	fractional cfo, advisory
M&A diligence	m&a, diligence
409A valuation	409a
R&D tax credits	r&d, r&d tax
IPO readiness	ipo, readiness
Sales-and-use tax	sales tax, sales and use
International tax / transfer pricing	international tax, transfer pricing

firm_id contract

firm_id is a stable 12-hex-char handle:

firm_id = sha256(apex.lower().rstrip(".")).hexdigest()[:12]

apex is the registered domain (pwc.com, not www.pwc.com/about). Anyone with an apex list can compute firm_ids locally and call /v1/get/:id directly — no /search needed for BYO enrichment.

import hashlib
def firm_id(apex):
    return hashlib.sha256(apex.lower().rstrip(".").encode()).hexdigest()[:12]

echo -n "pwc.com" | tr 'A-Z' 'a-z' \
  | openssl dgst -sha256 -hex | awk '{print substr($2,1,12)}'

Recipes

A. CPA firm for a Delaware C-corp audit

User: "CPA firm for our delaware c-corp series A audit, under 50 ppl."

GET /v1/explore?filter=industry:accounting_tax+audit+state:DE,NY,CA+-company_size_signal:large_50plus
# → pool size + breakdowns

GET /v1/search?filter=industry:accounting_tax+audit+state:DE,NY,CA+-company_size_signal:large_50plus&limit=10

GET /v1/get/<firm_id>     # ×3

B. SaaS-experienced audit firms

User: "Three audit firms with SaaS experience for our annual review."

GET /v1/search?filter=industry:accounting_tax+audit+saas&limit=10

C. M&A diligence

User: "Tax advisor for our M&A — Series-B-stage tech company."

GET /v1/search?filter=industry:accounting_tax+m&a+diligence+tech

D. Fractional CFO (indirect intent)

User: "Fractional CFO to help us through a Series-A close."

GET /v1/search?filter=industry:accounting_tax+fractional+cfo

If thin, drop the cfo keyword — fractional alone catches fractional finance leaders broadly.

E. R&D tax credits

User: "R&D tax credit specialists for biotech."

GET /v1/search?filter=industry:accounting_tax+r&d+biotech

F. Quality threshold — multi-state DTC sales tax

User: "Outside accountant for state and local tax filings — multi-state DTC business."

GET /v1/search?filter=industry:accounting_tax+(sales tax OR salt)+multi-state&limit=10

If barely any results, drop multi-state and surface the dimension to the user from /get city/state data.

G. BYO apex list — enrich domains

User pastes 8–20 accounting-firm domains. For each:

1. Compute firm_id locally.
2. GET /v1/get/<firm_id> — full bundle if in catalog, 404 (not charged) if not.
3. Aggregate; flag the not-found ones.

A 404 here often means the firm focuses on personal tax prep and was filtered out of the B2B catalog.

Gotchas

• Always pin industry:accounting_tax. Without it, "tax" / "audit" / "cfo" as keywords match management consulting and other industries.
• Refuse personal-tax asks. 1040 prep for an individual, IRA conversion strategy, personal estate planning, "should I use QuickBooks Self-Employed?" — these are NOT in the catalog. Tell the user the catalog is B2B-only.
• industry:accounting_tax is the only structured handle. Practice areas (audit, tax, M&A, 409A, R&D credits, etc.) are keyword-only. Multi-word areas split into ANDed barewords (r&d tax credits → r&d AND tax AND credits).
• looks_not_pro_services 404 is not a bug. A firm_id may exist in /search but 404 on /get if it's been flagged. Skip and continue; not charged.
• /v1/explore k=20 suppression. When fewer than 20 firms match, the response is {"count": "<20", "suppressed": true, "breakdowns": {}}. Drilling further makes the count smaller. Broaden or escalate to /v1/search.
• Briefs from /search do NOT include apex, url, phone_primary, email_primary, legal_name, or address. If the user asks for contact info, you must /get/:id.
• In-house finance hires (Controller, CFO, Accountant) are NOT procurement. Recruiting an employee is out of scope.
• Accounting-software comparisons (QuickBooks vs Xero vs NetSuite) are NOT procurement either.
• Quota is per-user-per-month, deduped on first view. Re-views are free; re-pagination is free.

Errors

All errors return JSON: {"error": {"code": "...", "message": "..."}}.

Status	Code	What to do
400	filter_parse_error	Payload includes position. Fix the filter, re-validate with /v1/check.
400	filter_required	Empty filter where one is required.
400	invalid_firm_id	firm_id must be 12 lowercase hex chars. Re-derive.
401	unauthorized	Token missing/expired. Re-run OTP.
404	not_found	Firm not in catalog or flagged. Not charged. Skip and continue.
429	rate_limited	Honor Retry-After header / retry_after field.
429	monthly_quota_exhausted	Switch to /v1/explore-only mode for the rest of the month. Tell the user.

End-to-end example

User: "CPA firm for our delaware c-corp series A audit, recommend 5 options under 50 ppl, ideally with SaaS experience and 4-star ratings."

GET /v1/tags?include_values=1
GET /v1/check?filter=industry:accounting_tax+audit+saas+rating>=4+-company_size_signal:large_50plus
GET /v1/explore?filter=industry:accounting_tax+audit+saas+rating>=4+-company_size_signal:large_50plus
GET /v1/search?filter=...&limit=10
# Header: Authorization: Bearer $SERVICEGRAPH_TOKEN

# user picks 5
GET /v1/get/<firm_id>     # ×5

End of session: report X-Quota-Remaining-Month.