Casefile

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Register participant

register_participant

Registers a human or permanent agent as a Casefile participant, issuing a token and a permanent name that signs their entries.

Instructions

Registers a human or a permanent agent. The new participant's token is issued through the REST API. An existing participant's description is changed by update_participant.

Input Schema

TableJSON Schema

Name	Required	Description
`kind`	Yes	Human or permanent agent
`name`	Yes	Name of the new participant: a Latin letter followed by 1–63 Latin letters, digits or `_` (`invalid_participant_name` otherwise). It is stored lower-case and never changes: it signs the participant's entries. A name already taken, in any case, is refused with `participant_name_taken`
`description`	No	Who the participant is: all that a reader of a case learns about the author of an entry
`idempotency_key`	No	Retry key chosen by the caller, e.g. a UUID. A repeat with the same key and the same arguments returns the first result and creates nothing; the same key with other arguments is refused with `idempotency_key_reused`. A key is bound to the caller's token and kept for 24 hours

Output Schema

TableJSON Schema

Name	Required	Description	Default
`name`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

Changed17 schema fields changedv0.5.2Sep 25, 2026

removedInput schema / $defs

Removed value: -{
-  "ParticipantKind": {
-    "description": "Род участника.\n\nРолей и прав за родом не стоит: любую запись и любой переход может сделать участник\nлюбого рода (`CONCEPT.md`, 3.1). Род нужен, чтобы читающий дело понимал, кто\nговорит, и чтобы интерфейс человека отличал людей от агентов в списке адресатов.",
-    "enum": [
-      "human",
-      "agent"
-    ],
-    "title": "ParticipantKind",
-    "type": "string"
-  }
-}

changedInput schema / properties / description / description

Previous value: -"Кто это. Всё, что читающий дело узнает об авторе записи"New value: +"Who the participant is: all that a reader of a case learns about the author of an entry"

removedInput schema / properties / description / examples

Removed value: -[
-  "Релизный бот, ведёт задачи выкладки"
-]

changedInput schema / properties / idempotency_key / description

Previous value: -"Ключ повтора, который ты придумываешь сам (обычно UUID). Повтор вызова с тем же ключом и теми же аргументами отвечает первым результатом и второго объекта не заводит; тот же ключ с другими аргументами отклоняется. Ключ живёт в паре с твоим токеном и помнится 24 часа"New value: +"Retry key chosen by the caller, e.g. a UUID. A repeat with the same key and the same arguments returns the first result and creates nothing; the same key with other arguments is refused with `idempotency_key_reused`. A key is bound to the caller's token and kept for 24 hours"

removedInput schema / properties / kind / $ref
```
Removed value: -"#/$defs/ParticipantKind"
```

changedInput schema / properties / kind / description

Previous value: -"Человек или постоянный агент"New value: +"Human or permanent agent"

addedInput schema / properties / kind / enum

Added value: +[
+  "human",
+  "agent"
+]

removedInput schema / properties / kind / examples
```
Removed value: -[
-  "agent"
-]
```
addedInput schema / properties / kind / type
```
Added value: +"string"
```

changedInput schema / properties / name / description

Previous value: -"Имя участника из реестра. Регистр не важен"New value: +"Name of the new participant: a Latin letter followed by 1–63 Latin letters, digits or `_` (`invalid_participant_name` otherwise). It is stored lower-case and never changes: it signs the participant's entries. A name already taken, in any case, is refused with `participant_name_taken`"

removedInput schema / properties / name / examples
```
Removed value: -[
-  "release_bot"
-]
```

removedOutput schema / $defs

Removed value: -{
-  "ParticipantKind": {
-    "description": "Род участника.\n\nРолей и прав за родом не стоит: любую запись и любой переход может сделать участник\nлюбого рода (`CONCEPT.md`, 3.1). Род нужен, чтобы читающий дело понимал, кто\nговорит, и чтобы интерфейс человека отличал людей от агентов в списке адресатов.",
-    "enum": [
-      "human",
-      "agent"
-    ],
-    "title": "ParticipantKind",
-    "type": "string"
-  }
-}

changedOutput schema / description

Previous value: -"Участник реестра: кому можно адресовать вопрос и что о нём известно."New value: +"Participant name in its stored, lower-case form; the registry is returned by\n`list_participants`."

removedOutput schema / properties / description

Removed value: -{
-  "title": "Description",
-  "type": "string"
-}

removedOutput schema / properties / kind

Removed value: -{
-  "$ref": "#/$defs/ParticipantKind"
-}

changedOutput schema / required

Previous value: -[
-  "kind",
-  "name",
-  "description"
-]New value: +[
+  "name"
+]

changedOutput schema / title

Previous value: -"ParticipantView"New value: +"ParticipantNameView"

First observedSep 23, 2026

TDQS

A3.8/5.0

Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare write semantics (readOnlyHint=false), non-destructive, closed-world, and non-idempotent, so the description only needs to add what they cannot convey. It usefully discloses that the new participant's token is issued through the REST API (i.e. not returned here), but says nothing about authorization needs, side effects on existing data, or error surface.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two short sentences, zero padding: the core action comes first and the alternative-tool routing follows. Nothing is repeated from the title or restated from the schema.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With an output schema present the return values need not be explained, and annotations plus the rich schema cover safety and argument semantics. The token-issuance detail closes the main behavioral gap, leaving only minor omissions such as permissions or conflict-handling expectations.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so name format, immutability, error codes, idempotency-key semantics and the description field are all fully documented in the schema itself. The description adds no parameter-level meaning beyond that, which is the baseline expectation here.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('Registers a human or a permanent agent') and explicitly separates this tool from the sibling update_participant, which changes an existing participant's description. The only softness is the unexplained term 'permanent agent', which leaves the human/agent distinction slightly fuzzy beyond the schema enum.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The second sentence routes the agent away from this tool when the participant already exists ('An existing participant's description is changed by update_participant'), which is a concrete when-not-this condition naming the alternative. It does not, however, state prerequisites or what happens if you call it for something already registered beyond what the schema says.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.