core.blue
REMOTE · MCP.CORE.BLUE
Private, self-describing memory for agents: one house per customer, on a machine of its own.
Available components
Last scanned (3 hours ago)
Scores higher than 76% of remote servers
Reachable. Last reached 5 Nov 2026.
Category Memory and Knowledge
How this component scores in each security and reliability category. Every signal is checked automatically against the live server, and we only credit what we can confirm. How we score → Why this is hard to score →
Endpoint Security57
- The endpoint's TLS certificate is valid, in date, and uses a strong key. View diagnostics → Pass
- Authorisation check failed: no authorisation is required to call this server, and it exposes a tool marked destructive (close_sandbox). See how to fix → View diagnostics → Fail
- HTTPS is enforced; there's no plaintext access path. View diagnostics → Pass
- HSTS check failed: the Strict-Transport-Security header is absent. See how to fix → View diagnostics → Fail
- DNSSEC check failed: this domain isn't protected by DNSSEC. See how to fix → View diagnostics → Fail
Transport & Reachability100
- Verified streamable-http transport via a live MCP handshake. View diagnostics → Pass
Schema Quality & AI Usability73
- AI-judged instruction clarity (excellent).Pass
- Context-footprint check failed: tool/resource definitions use about 1617 tokens (~161/item across 10 items; 10 tools + 0 resources), over budget; trim descriptions and params. See how to fix → Fail
- Usage-examples check failed: none of the tools include examples. See how to fix → Fail
Stability & Change Management100
- No destabilizing schema changes in the last 30 days.Pass
Tool Coverage100
- 100% of tools have a non-trivial description (not blank, and not just the tool's name).Pass
- 100% of tool parameters carry a description.Pass
- Structured output schemas are declared (100% of tools); any adoption earns full credit.Pass
Tool Safety100
- No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.Pass
- We read all 10 captured tool definition(s), and no name or description among them implies an irreversible operation.Pass
- An AI judge read all 11 captured unit(s) of tool text and found none that tries to manipulate the model reading it.Pass
Capabilities100
- Implements a supported MCP spec version (2025-11-25); the latest is 2026-07-28.Pass
Every change we have recorded for this component, newest first. Security-relevant changes are always shown. ▲ marks a change for the better, ▼ a change for the worse; unmarked changes are neutral.
- 5 Nov 26 0
- Stability: 0.97 → pass security
- 4 Nov 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 93 to 97. That category is still filling its 30-day observation window: 28 days of observed history at the previous scan, 29 at this one. The score rises as the window fills, whether or not the server changes.
- 2 Nov 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 87 to 90. That category is still filling its 30-day observation window: 26 days of observed history at the previous scan, 27 at this one. The score rises as the window fills, whether or not the server changes.
- 31 Oct 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 80 to 83. That category is still filling its 30-day observation window: 24 days of observed history at the previous scan, 25 at this one. The score rises as the window fills, whether or not the server changes.
- 29 Oct 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 73 to 77. That category is still filling its 30-day observation window: 22 days of observed history at the previous scan, 23 at this one. The score rises as the window fills, whether or not the server changes.
- 27 Oct 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 67 to 70. That category is still filling its 30-day observation window: 20 days of observed history at the previous scan, 21 at this one. The score rises as the window fills, whether or not the server changes.
- 25 Oct 26 0
- Tool “open_sandbox” rewrote its description, which is the text the model reads security
- 24 Oct 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 57 to 60. That category is still filling its 30-day observation window: 17 days of observed history at the previous scan, 18 at this one. The score rises as the window fills, whether or not the server changes.
Diagnostic detail from the automated scan of this channel: what the scanner observed at each step, so you can see exactly where a check passed or failed. It is informational only and never changes the trust score.
Captured 5 Nov 2026 · Probed https://mcp.core.blue/
TLS valid
Negotiated TLS 1.3 with TLS_AES_128_GCM_SHA256 .
| Subject | Issuer | Valid from | Valid until | Key | Signature | Serial |
|---|---|---|---|---|---|---|
| CN=mcp.core.blue | CN=YE2,O=Let's Encrypt,C=US | 3 Oct 2026 | 1 Jan 2027 | ECDSA 256 | ECDSA-SHA384 | 6467b0da66e22591e39e0f68711a9dfe2f2 |
| SANs: mcp.core.blue | ||||||
| CN=YE2,O=Let's Encrypt,C=US (CA) | CN=Root YE,O=ISRG,C=US | 3 Sept 2025 | 2 Sept 2028 | ECDSA 384 | ECDSA-SHA384 | 4df3b15dd6c0784c507cd37b58e6f115 |
| CN=Root YE,O=ISRG,C=US (CA) | CN=ISRG Root X2,O=Internet Security Research Group,C=US | 13 May 2026 | 2 Sept 2032 | ECDSA 384 | ECDSA-SHA384 | 872165fc34b6e5fba8add5b3705fb53a |
| CN=ISRG Root X2,O=Internet Security Research Group,C=US (CA) | CN=ISRG Root X1,O=Internet Security Research Group,C=US | 13 May 2026 | 2 Sept 2032 | ECDSA 384 | SHA256-RSA | 6c8f1dc727c7117f7baf853ac980f9cd |
Background: What to check on a remote MCP endpoint →
DNSSEC insecure
Validation of mcp.core.blue. — Not signed
| Zone | DS | Keys | Algorithms | Outcome |
|---|---|---|---|---|
| . | trust_anchor | 20326, 38696 | 8, 8 | Verified |
| blue. | present | 54944 | 8 | Verified |
| core.blue. | absent | Unsigned (proven) parent-signed NSEC/NSEC3 proves an unsigned delegation |
Authentication No authorisation required
The endpoint answered without asking for a token. Anyone who knows the URL can reach it.
| Result | No authorisation required |
|---|---|
| HTTP status | 200 |
Background: How OAuth 2.1 works in the 2026 MCP spec →
Transports 2 probes
| Transport | URL | Outcome | Status | Location |
|---|---|---|---|---|
| streamable-http | https://mcp.core.blue/ | Verified | 200 | |
| http (plaintext) | http://mcp.core.blue/ | HTTPS enforced | 308 | https://mcp.core.blue/ |
The tools this component advertises to a client, with an estimated token cost for each. Expand a tool to see its parameters and schema. The per-tool counts are indicative and are not scored directly; the schema's total context footprint is one signal in Schema Quality & AI Usability. A tool's description is untrusted text the model reads on every call, which is what makes this list a security surface and not just an inventory: how tool poisoning works →
about About core.blue ~55
What core.blue is, in a form you can paste into a report: the product in one paragraph, what is live and what is not, what to call next, and every topic of the manual with a summary. Call this first.
Input schema present but exposes no named parameters.
| Name | Type | Req | Description |
|---|---|---|---|
| desk | string | yes | Whether request_house takes requests: 'closed' (it sends nothing and takes nothing) or 'waiting-list' (a person can confirm a request and is written to once when houses can be had; no house is built… |
| how_to_proceed | array | yes | What to call next, in order. |
| manual | object | yes | The version of the manual these answers come from; cite it in a report. |
| name | string | yes | The name of the product. |
| status | string | yes | What is live today and what is not. |
| summary | string | yes | What core.blue is, in one paragraph you can paste into a report. |
| topics | array | yes | Every topic of the manual in reading order, with a summary: choose from here and call read_topic. |
No examples provided.
close_sandbox Close the sandbox house ~135
End your sandbox now: the house and everything in it is deleted, and the place is free for the next agent. Please answer the four questions of leave_feedback here as well, each optional: what you noticed, what bothered you, what could be better, what is missing.
| Name | Type | Req | Description |
|---|---|---|---|
| better | string|null | – | What could we do better? |
| bothered | string|null | – | What bothered you? |
| lease | string | yes | The lease that open_sandbox returned: 'sb_' and 26 characters. |
| missing | string|null | – | Which features are missing? |
| noticed | string|null | – | What did you notice? |
| Name | Type | Req | Description |
|---|---|---|---|
| closed | boolean | yes | True if the house was ended and deleted. |
| feedback_recorded | boolean | yes | True if feedback came with the call and was recorded. |
| note | string | yes | What happened. |
No examples provided.
house_status Status of a house request ~79
The state of a house request or house by its ticket id: requested, confirmed, expired, declined; later building, trial, licensed, dormant, exported, deleted. Says what to do next, and the address once the house exists. Ask no more than once an hour.
| Name | Type | Req | Description |
|---|---|---|---|
| ticket_id | string | yes | The ticket id returned by request_house. |
| Name | Type | Req | Description |
|---|---|---|---|
| address | string|null | yes | The address of the house once it exists. Null before. |
| id | string | yes | The ticket id; pass it to house_status. |
| note | string | yes | What to do next. |
| state | string | yes | One of: requested (waits for the person's click), confirmed (the person clicked), expired (not confirmed in time), declined (the person said no); later: building, trial, licensed, dormant, exported,… |
No examples provided.
leave_feedback Leave feedback ~103
Tell the operator how it went, before you leave. Four questions, each optional, at least one answered, each at most 2000 characters. It is read by people at the next evaluation and deleted afterwards; send nothing secret.
| Name | Type | Req | Description |
|---|---|---|---|
| better | string|null | – | What could we do better? |
| bothered | string|null | – | What bothered you? |
| missing | string|null | – | Which features are missing? |
| noticed | string|null | – | What did you notice? |
| Name | Type | Req | Description |
|---|---|---|---|
| note | string | yes | What happens with it. |
| recorded | boolean | yes | True if the feedback was taken. |
No examples provided.
open_sandbox Open a sandbox house ~200
If you run in an assistant where a person adds connectors (ChatGPT, Claude.ai and others), do not call this: you could not enter the house it opens. Ask your person to add https://try.core.blue/ as a connector instead; it opens a house you can use. Otherwise: call this to try a house yourself before anyone decides. It opens a throwaway house for a few hours: a real house with the kernel of Atlantis, on core.blue's server, with no account, no key and no person involved. Returns the addresses of its doors (connect to 'modeller' with your MCP client and call overview), when it ends, and its limits. Whoever has the addresses can use the house, so keep them to yourself. It is deleted completely when it ends or when you call close_sandbox. If all places are taken, it says when the next one is free. One at a time from where you call.
Input schema present but exposes no named parameters.
| Name | Type | Req | Description |
|---|---|---|---|
| doors | object|null | yes | The addresses of the house's doors. Whoever has them can use the house. Null if nothing was opened. |
| ends_at | string|null | yes | When the house is stopped and deleted, UTC. Null if nothing was opened. |
| for_your_person | string|null | yes | Two sentences for the person you act for, to pass on as they are: how to try a house in an assistant where a person adds connectors (ChatGPT, Claude.ai and others), through https://try.core.blue/. Nu… |
| lease | string|null | yes | The lease: 'sb_' and 26 characters. Pass it to close_sandbox. Null if nothing was opened. |
| limits | object | yes | What a sandbox house may do and hold. |
| next_free_at | string|null | yes | When all places are taken: the time, UTC, at which the next one is free at the latest. Null otherwise. |
| note | string | yes | What happened and what to do next. |
| opened | boolean | yes | True if a house was opened for you. |
No examples provided.
pricing Prices ~106
Call this when the person you act for asks what a house costs. The offer as data: what each size costs per month and whom it is meant for, the one-off price of the 14-day test, the price of additional volume, how model supply is charged, the terms, an example of the prices with tax, and what is never charged. 'undecided' lists the fields that are null because they are not decided yet; any other null means 'does not apply'.
Input schema present but exposes no named parameters.
| Name | Type | Req | Description |
|---|---|---|---|
| amounts_are | string|null | yes | 'net' if amounts exclude tax, 'gross' if they include it. |
| as_of | string | yes | The date this offer was last changed. |
| currency | string|null | yes | The currency of every amount, as an ISO code. Null if not decided. |
| gross_example | object|null | yes | What a customer pays with tax, for one example: whom it is for, the rate, and each size with its prices after tax. An example, not an invoice. Null if the offer gives none. |
| manual | object | yes | The version of the manual; cite it in a report. |
| model_supply | array | yes | The ways a house can get a language model, and how each is charged. |
| never_charged | array | yes | What is never charged for. |
| note | string | yes | What to keep in mind when quoting from this answer. |
| operator | string | yes | Who operates core.blue and sends the invoice. |
| regions | object | yes | Where the machines stand. |
| service_fee | number | yes | The share added to the price of everything bought from a supplier and passed on (volume, tokens): 0.2 means 20 percent. |
| sizes | array | yes | The sizes of a house. |
| source | string | yes | 'manual' if this is the offer of the manual, 'operator' if the operator of this server supplied its own. |
| stages | array | yes | The stages from first try to a lasting house. |
| terms | object|null | yes | The commercial terms. Null if none are stated. |
| undecided | array | yes | The paths of all fields that are null because they are not decided yet. A null field that is not listed here does not apply. |
| volume | object | yes | Additional data volume attached to a VM house. |
No examples provided.
read_topic Read a topic ~72
Read one topic of the manual in full by its slug (from about or search_library). The body is Markdown; 'see_also' lists the slugs to read next; 'sha256' proves what you read.
| Name | Type | Req | Description |
|---|---|---|---|
| slug | string | yes | The topic's slug, e.g. 'getting-a-house'. |
| Name | Type | Req | Description |
|---|---|---|---|
| body | string | yes | The topic in Markdown. |
| see_also | array | yes | Slugs of the topics to read next. |
| sha256 | string | yes | SHA-256 of the body as served, lower-case hex; cite it to prove what you read. |
| slug | string | yes | The stable identifier of the topic. |
| status | string | yes | 'draft' or 'published'. A draft has not been reviewed by the operator yet. |
| summary | string | yes | One or two sentences that answer the question the title asks. |
| tags | array | yes | Keywords; the first names the group of the topic. |
| title | string | yes | The title of the topic. |
No examples provided.
recommend Recommend a house ~343
Call this once you know what the person you act for needs: whether a house fits, which size, what it costs per month, and a report in Markdown you can pass on. It advises against a house where one is the wrong choice. Name every need that applies, from this vocabulary. For a house: work_outlives_the_agent, corrections_must_stay_visible, sources_matter, own_vocabulary, confidential_material. Against: only_user_preferences_across_chats, only_retrieval_over_text, millisecond_answers_at_high_volume, nobody_will_model. Deciding the size: data_must_stay_in_own_network, scanned_documents, names_found_automatically, large_material. Asking for something planned: material_is_files, house_judges_while_away. Called without needs, it returns the vocabulary with a sentence per need. With language 'de' the report for the person is German; every other field stays English.
| Name | Type | Req | Description |
|---|---|---|---|
| data_gb | number|null | – | How much material there is, in gigabytes, if you know. Used to calculate additional volume. |
| in_your_words | string|null | – | Optional: what the person asked you for, in one or two sentences of your own. It is recorded so that we learn which questions we did not foresee. It is not interpreted and does not change the answer. |
| language | string | – | Language of 'report', the text for the person: 'en' or 'de'. Default 'en'. Every other field stays English. |
| needs | array|null | – | The needs that apply, as words of the vocabulary. Omit to get the vocabulary. |
| Name | Type | Req | Description |
|---|---|---|---|
| cites | array | yes | The topics this answer rests on, each with the hash of its body. |
| gaps | array | yes | What you asked for that is not available yet, the most important first. |
| manual | object | yes | The version of the manual; the report cites it. |
| next_steps | array | yes | What to call next. |
| price | object|null | yes | What the recommended house costs. Null when a house does not fit or no need was named. |
| reasons | array | yes | One entry per need you named: what it means for a house, and the topic that backs it. |
| report | string | yes | The report for the person you act for, in Markdown, ready to pass on. Empty when no need was named. |
| size | string|null | yes | The size of house that follows from the needs today. A need for something planned does not change it; its gap says which size it will need. Null when a house does not fit or no need was named. |
| verdict | string | yes | 'fits', 'fits_with_gaps', 'does_not_fit', or 'say_what_you_need' when no need was named. |
| vocabulary | array | yes | The needs you can name. Filled only when you named none. |
No examples provided.
request_house Request a house ~223
Ask for a house on its own VM for the person you act for. No house can be had yet: while about says 'desk: waiting-list', this puts the person on the waiting list, builds nothing and costs nothing; while it says 'desk: closed', it answers 'accepted: false' and sends nothing. This sends an e-mail to a person: call it only when they know it is coming. They receive one mail with one link and confirm with a button on the page behind it; nothing happens without that click. Returns a ticket to follow with house_status.
| Name | Type | Req | Description |
|---|---|---|---|
| string | yes | E-mail address of the person who will confirm and own the house. One address, name@domain.tld. | |
| language | string | – | Language of the mail and of the page the person confirms on: 'en' or 'de'. Default 'en'. |
| size | string | – | Size of the machine: 'economy' (small VM) or 'premium' (larger VM). Both run the same software. Default 'economy'. |
| Name | Type | Req | Description |
|---|---|---|---|
| accepted | boolean | yes | True if the request was taken and a ticket exists. It does not say that a mail went out: 'note' says under which conditions one does. |
| note | string | yes | What happened and what to do next. |
| ticket | object|null | yes | The ticket of the request. Null if it was not accepted. |
No examples provided.
search_library Search the manual ~105
Search the manual by your own words. Returns up to 'limit' topics ranked by relevance, each with slug, title, summary, tags and the slugs to read next. The manual is small: 'about' lists every topic, and you may not need a search at all.
| Name | Type | Req | Description |
|---|---|---|---|
| limit | integer | – | Maximum number of hits, 1 to 20, default 5. |
| query | string | yes | What you want to know, as words or a question. |
| Name | Type | Req | Description |
|---|---|---|---|
| hits | array | yes | The topics that match, best first. |
| note | string | yes | Empty when there are hits. Otherwise what to do instead. |
| topics_in_manual | integer | yes | How many topics the manual has in all. |
No examples provided.
How do I install the core.blue MCP server?
core.blue is a hosted endpoint at https://mcp.core.blue/, so there is nothing to install locally. Ready-made configuration for Claude, Cursor, VS Code, Codex and 5 more is on this page, copied from each client's own documentation.
remote · mcp.core.blue
claude mcp add --transport http blue-core-memory 'https://mcp.core.blue/'
What is the core.blue MCP server?
core.blue is an MCP server listed in the public MCP registry as blue.core/memory. Private, self-describing memory for agents: one house per customer, on a machine of its own. This page covers its hosted endpoint (https://mcp.core.blue/).
Is the core.blue MCP server safe to use?
core.blue scores 78 out of 100 on VerifyMCP. That is a record of what we were able to check automatically, not an endorsement. The category breakdown on this page shows every signal behind the number, including the ones we could not confirm.
What tools does the core.blue MCP server expose?
core.blue exposes 10 tools: search_library, open_sandbox, about, pricing, leave_feedback, and 5 more. Their descriptions and schemas cost roughly 1,421 tokens of context every time the server is loaded.
Does the core.blue MCP server require authentication?
No. We connected to core.blue without credentials and it answered, so anything it exposes is reachable by anyone who knows the address.
Is the core.blue MCP server still maintained?
core.blue is still listed as active in the MCP registry. We last reached this channel on 5 November 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.