set_pool_pg_num

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

Annotations already declare the mutation profile (readOnlyHint=false, destructiveHint=true, idempotentHint=false), but the description adds genuinely new context: a [WRITE][risk=medium] tag and, importantly, that the change is reversible to the prior pg_num (matched by the undo_list/undo_apply siblings). This is useful beyond what annotations provide.

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

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

Front-loads the mutation/risk tags and one-line purpose before a scannable Args block. Every line carries information with no filler.

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

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

For a destructive, non-idempotent 3-param mutate tool with no output schema, the description covers purpose, risk, reversibility, and every parameter. It could go further on consequences (data rebalancing load, health-state preconditions), but is largely complete.

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

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

Schema coverage is 0%, so the description carries the full burden, and it documents all three parameters: pool_name (with its source tool), pg_num (new placement-group count), and target (Ceph target name, omit for default). It only omits validation detail such as pg_num power-of-two expectations.

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

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

States a precise verb and resource ('Set a pool's pg_num'), naming the exact configuration field being mutated. This clearly separates it from sibling setters such as set_pool_size, set_pool_quota, and set_pool_autoscale.

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

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

Usage is only implied: 'pool_name (from pool_ls)' hints that pool_ls must be called first to discover a valid name, and target notes 'omit for the default'. There is no explicit statement of when to prefer this over set_pool_autoscale or any prerequisite about cluster health before rebalancing.

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