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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds value beyond that by disclosing what is actually returned (folders, rooms, recent notes, user rules) and by specifying it is a once-per-session call, which prevents redundant invocation. It does not mention response size or cost, which for a whole-vault overview could matter.

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, front-loaded with 'Start here' so the agent sees the routing cue first. Every sentence carries distinct information: purpose, payload contents, and invocation timing. 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?

With no parameters, no output schema, and read-only annotations, the description carries the burden of saying what comes back — and it does, enumerating the four payload categories. It is slightly incomplete in not hinting at response volume or how to use the returned rules, but nothing needed to call 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?

The tool takes zero parameters, so there is nothing for the description to disambiguate; baseline 4 applies. The schema is empty and fully described by construction.

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 ('Returns') and enumerates the resource contents: folder structure, rooms, recently changed notes, and user rules from the system folder. The 'Start here' opener plus the enumeration distinguishes it cleanly from every sibling, all of which operate on individual notes.

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?

Gives explicit timing guidance — 'Call this once at the start of a session' — which is exactly the when-to-use signal an agent needs. It does not name an alternative or state when not to call it (e.g. re-calling mid-session), so it falls short of full routing guidance.

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