Robin Saige we check the tools AI agents call

excalibur mcp

io.github.lonniev/excalibur-mcp

FastMCP server for posting formatted content to X (Twitter) — Tollbooth-monetized, DPYC-native

— the operator's own registry description reported

Publisher io.github.lonniev · first seen 2026-08-12 · endpoint https://excalibur-mcp.fastmcp.app/mcp

allow
verdict
rich-solo
cluster
ok_tools
answers
77
tools served

Dependency rating derived

allow
allow — alive & usable · action ● · V n/a
allow — because answers ●, 77 tools legible (band B) ●, no confirmed drift in 2 probes ●; not yet checked: truth (0 runs)

Cluster rich-solo · distinctiveness 0.657 (unusual). Every figure is a percentile or class within the 11,094-server censussee the whole spectrum.

Does it answer? Q1 · observed
answersalive_tools
latency191 ms
vs populationtypical
protocolcurrent
authopen
Can it be used? Q4 · observed
tools77
vs populationhigh
capabilities5
harnessB
Did it hold when checked? Q3–Q4 · derived
identitysolo
servers on its host1
verifiabilityunassessed
duplicate inventoryno
drift events0
answers trueno primary

🔏 Signed receipt rr_defd3b4a0ca50b60da0ed4cc · ed25519 · key rs-rcpt-2026-08 — this rating is tamper-evident; an agent gets the full signature from check_server and can verify it against the published key.

Q1Does it answer?alive & usable — 2 probes ●evidence ↓
Q2What is it?action ● evidence ↓
Q3Can it be checked?V n/a for this kind ◐evidence ↓
Q4Did it hold?harness B · truth not yet run · no drift ●evidence ↓
Q5What company does it keep?rich-solo · 1 on its host (context, not verdict) ◐evidence ↓

● observed · ◐ derived · ○ reported — the verdict synthesizes Q1–Q4; Q5 is context. Methodology →

History observed

Every probe we made, oldest → newest (2 shown, 2026-08-12 → 2026-08-14). Green answered · amber answered-but-walled · red no useful answer. A gap in our cadence is a gap in coverage, not evidence about the server.

changelog (1 events)
datetypewhat changed
2026-08-12outcomefirst probe: ok_tools

What kind of tools these are derived

Verification only means something relative to a tool's NATURE — an email-sender has no "true answer", a generator has no answer key. Classification evidence: classified from tool names/descriptions/annotations WE OBSERVED. What checking applies to each kind (the full methodology →):

naturetoolsmeaning what checking applies
action53changes the worldno true answer exists; we check the CONTRACT (destructive/read-only/idempotent declarations, error legibility) and never fire real actions
retrieval-public19serves public factstruth-checkable against a public source — the V-ladder applies in full
unclassified4not classifiable from its textTier-1 only until its tools describe themselves
generative1creates contentno answer key exists; disclosure + stability checks, never truth verdicts

Tools last seen observed

excalibur_account_statement excalibur_account_statement_infographic excalibur_adoption_status excalibur_begin_oauth excalibur_check_authority_balance excalibur_check_balance excalibur_check_oauth_status excalibur_check_payment excalibur_check_price excalibur_check_proof_status excalibur_create_post excalibur_delete_coupon excalibur_delete_patron_credential excalibur_delete_post excalibur_delete_snippet excalibur_fetch_dynamic_block excalibur_forget_coupon excalibur_forget_credentials excalibur_get_nostr_profile excalibur_get_notarization_proof excalibur_get_operator_onboarding_status excalibur_get_patron_credential_fields excalibur_get_patron_onboarding_status excalibur_get_post excalibur_get_post_metrics excalibur_get_pricing_model excalibur_get_scheduler_log excalibur_get_snippet excalibur_get_voice excalibur_get_x_profile excalibur_harvest_metrics excalibur_list_canonical_identities excalibur_list_constraint_types excalibur_list_coupons excalibur_list_my_coupons excalibur_list_notarizations excalibur_list_posts excalibur_list_snippets excalibur_mint_coupon excalibur_notarize_ledger excalibur_oracle_about excalibur_oracle_get_tax_rate excalibur_oracle_how_to_join excalibur_oracle_lookup_member excalibur_oracle_network_advisory excalibur_post_nostr_message excalibur_post_performance excalibur_post_performance_infographic excalibur_post_tweet excalibur_post_tweet_image excalibur_process_scheduled_posts excalibur_publish_nostr_profile excalibur_purchase_credits excalibur_receive_credentials excalibur_receive_npub_proof excalibur_redeem_coupon excalibur_refine_post_region excalibur_report_issue excalibur_request_adoption excalibur_request_credential_channel excalibur_request_npub_proof excalibur_reset_pricing_model excalibur_resolve_dynamic_block excalibur_restore_credits excalibur_restore_neon_schema excalibur_save_snippet excalibur_save_voice excalibur_scheduler_check_now excalibur_scheduler_pending excalibur_scheduler_status excalibur_service_status excalibur_session_status excalibur_set_pricing_model excalibur_update_coupon excalibur_update_operator_credential excalibur_update_patron_credential excalibur_update_post

Harness readiness observed

Can an agent's harness pick this tool and call it correctly? Graded on the three things an agent reads — name, description, typed parameters. Band B — usable, with rough edges.

legibility checktools passingok
name is clear & specific77/77
has a description77/77
description is substantive77/77
parameters are typed77/77
parameters are described11/7711/77

77 of 77 tools graded · 77 with a captured input schema. RS-008, Tier-1 — no domain knowledge, applies to any tool. “Alive” is not the same as “usable”.

Truth checks observed

Not in the Tier-2 trade lane, or not yet checked. Tier-2 re-derives a server's answers against published primary sources — see truth checks.

Protocol conformance observed

2025-06-18
protocol version
session model
3.0.2
server version eXcalibur

Capabilities: experimental extensions prompts resources tools

Drift observed

No confirmed drift on record. Baseline set 2026-08-14; changes appear here after human review.

raw probe records
probed (UTC) outcomehttpmsprotocol
2026-08-14T19:59:44Zok_tools2001912025-06-18
2026-08-12T05:34:57Zok_tools2002312025-06-18

Watch or embed this verdict

verdict badge

Operators: put the live verdict in your README — it updates with every census, links back here, and is a dated observation, never a warranty:

[![Robin Saige verdict](https://robinsaige.com/badge/io.github.lonniev/excalibur-mcp.svg)](https://robinsaige.com/s/io.github.lonniev/excalibur-mcp)

Depend on it? Subscribe to its change feed — outcome changes and confirmed drift, no account needed. Building on it? The full dossier as JSON — verdict, rating, truth checks, history — stable enough to gate CI on.

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