io.github.AIops-tools/ceph-aiops

set_pool_size

Destructive

Set a Ceph pool's replica count with dry-run preview, blocking reductions on mgr-owned pools that can disrupt Dashboard operations.

Instructions

[WRITE][risk=high] Set a pool's replica size — forces mass data movement on a live pool.

Pass dry_run=True to preview. Reversible → prior size.

Refuses a size REDUCTION on .mgr / .rgw.root and any mgr-owned pool: fewer replicas degrades ceph-mgr, which serves the Dashboard REST API this tool speaks — so the recorded undo would have no transport to travel over. RAISING the size on those pools is allowed. Enforced under dry_run too.

Args: pool_name: Pool name (from pool_ls). size: New replica count. dry_run: If True, preview without changing the size. target: Ceph target name from config; omit for the default.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "pool_name": "<pool_name>",
      "size": "<size>"
    },
    "name": "set_pool_size"
  }
}

Input Schema

Name	Required	Description	Default
`size`	Yes
`target`	No
`dry_run`	No
`pool_name`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Jul 12, 2026

TDQS

A4.8/5.0

Behavior5/5

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

Annotations already declare destructive=true, readOnly=false, idempotent=false, so the safety profile is covered. The description adds substantial context beyond them: mass data movement on a live pool, reversibility to the prior size, the exact pools where reduction is refused, and that the guard applies under dry_run.

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

Conciseness4/5

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

Front-loaded with the risk tag and the core action, then the preview/reversibility facts, then the refusal rules and Args. Every clause is informative, though the explanation of the mgr/REST-API cause is somewhat verbose for what it adds.

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

Completeness5/5

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

For a high-risk mutation with no output schema, the definition supplies everything an agent needs: safety profile via annotations, reversibility, preview path, and the full set of refusal conditions plus parameter meanings. No output schema exists, so return values need not be described.

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

Parameters4/5

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

With 0% schema coverage the description carries the full burden, and it documents all four parameters: pool_name (with a source pointer to pool_ls), size (new replica count), dry_run (preview semantics), and target (config name, omit for default). It lacks any constraint or range detail for the integer size, a small gap given the empty schema.

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

Purpose5/5

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

States a specific verb+resource ('Set a pool's replica size') and immediately distinguishes itself from sibling pool mutators like set_pool_pg_num, set_pool_quota, and set_pool_autoscale. The '[WRITE][risk=high]' tag and the 'forces mass data movement on a live pool' clause give the agent the operation's character at a glance.

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

Usage Guidelines5/5

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

Explicitly says when to use it ('Pass dry_run=True to preview'), when it will refuse (size reduction on .mgr/.rgw.root and mgr-owned pools), and what is still allowed (raising size on those pools). It even notes the refusal is enforced under dry_run. The pool_name provenance ('from pool_ls') is stated.

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