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

Annotations already declare readOnlyHint=false, idempotentHint=true, destructiveHint=false. The description adds genuinely new behavioral context: the selection persists across later sessions, and no data is copied between brains — the latter pre-empts a plausible mistaken expectation about a write-labeled tool.

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?

Three short sentences, action front-loaded, each carrying distinct information (what changes, how to enumerate, persistence, no data movement). 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?

No output schema exists, and the description plus annotations cover the mutation target, persistence, and scope of side effects. Minor gaps remain around failure handling for an unknown brain name, but nothing essential to calling it correctly is missing.

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 100% and the single parameter already documents 'Name (case-insensitive) or id of the brain to use'. The description's 'by name or id' restates that, adding no syntax or matching detail beyond the schema. Baseline 3 applies.

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 specific verb and resource ('Switch which ... brains this connector reads and writes') with the selector format (name or id). It is clearly distinguishable from siblings like brain_memorize/brain_recall and points at brain_status for enumeration.

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?

Implies the use case (change the active brain for this connector) and names the companion tool for listing available brains. It does not state exclusions or error behavior when the named brain doesn't exist, so it stops short of explicit when-not guidance.

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