List controllers

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

Annotations already declare read-only/idempotent/non-destructive, so the restated 'Read-only: this server cannot move the robot or change anything' is only mild redundancy — and it usefully scopes the guarantee to the whole server. The description adds real context the annotations cannot: controller text is untrusted data (prompt-injection warning) and the agent must flag stale or replayed data.

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?

Four short sentences, front-loaded with what it does, then when to call it, then safety properties. No filler, and the most decision-relevant clause ('Call it first') appears early.

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?

An output schema exists, so return values need not be explained. Combined with annotations and the injection/staleness warnings, an agent has everything needed to call this correctly first in a session and interpret its output responsibly.

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 and the schema is empty, so there is nothing for the description to document; baseline 4 applies. The description correctly implies no input is needed.

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 ('Lists the controllers the daemon knows') plus an extra scope element ('the daemon's own state') that distinguishes it from the per-controller siblings like get_controller_status and summarize_controller. An agent can tell immediately that this is the enumeration/discovery entry point.

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 sequencing advice ('Call it first, and when other tools fail'), which is strong guidance for a discovery tool. It does not name a specific sibling as an alternative for any case, so it falls short of the 5 bar, but the intended usage is unambiguous.

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