extensions_list

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

With no annotations at all, the description bears the full burden of behavioral disclosure. It conveys the observable state values (running, loading, failed) and that load errors are included, which is useful, but it never states that this is a non-mutating read, what happens if the emulator is not running, or how ordering/pagination works.

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?

A single dense sentence with no filler, and the most important content (what instances are returned and their state) is front-loaded. The phrasing is slightly awkward as an unpunctuated noun phrase, but nothing is wasted.

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 zero-parameter list tool with no output schema, the description does the heavy lifting by sketching the returned fields: reference, version, state, load error, function count. That is reasonably complete for the return shape, but the absence of any statement about read-only behavior or emulator preconditions leaves a gap.

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 the baseline is 4 by rule; there is nothing for the description to clarify about inputs, and it correctly spends no words on parameter semantics.

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?

The description names the resource ('Firebase Extensions instances the suite runs') and enumerates its fields, so an agent can infer this is a read/list operation. But there is no explicit verb — it is a noun phrase describing contents rather than stating 'list all extension instances', and it never distinguishes itself from siblings like extensions_reload.

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?

No when-to-use guidance, no mention of prerequisites (e.g. that the emulator/suite must be running, which the phrase 'the suite runs' only hints at), and no routing to or from extensions_reload. The agent must guess that reload is the mutation counterpart.

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