instance_list

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

With no annotations, the description carries the full burden; it implies a read-only listing and discloses the returned fields and the token-cost tradeoff between formats, which is useful. It says nothing about scope limits (all instances vs. pagination), auth requirements, or rate limits.

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?

The listing purpose is front-loaded, followed by clearly labelled Args and Returns sections with no filler. The structure is slightly verbose for a one-parameter tool but every sentence carries information.

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?

Although an output schema exists (so return-value detail is not strictly required), the description adds the compact/json choice semantics an agent needs to call it well. Only the absence of scoping/pagination behavior keeps it from a 5.

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 description coverage is 0% for the single 'format' parameter, so the description must compensate, and it does: it names both allowed values, marks 'compact' as the default with 'one line per instance', and explains the practical token tradeoff. It does not describe exact JSON structure, keeping it short of a 5.

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 states a specific verb and resource ('List all instances in your account'), which cleanly separates it from the many singular instance siblings such as instance_get and instance_update. It stops short of naming a sibling or stating what it excludes, so it is clear but not fully differentiated.

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?

There is no explicit when-to-use guidance or mention of alternatives. The only contextual hint is that compact format is 'far cheaper in tokens for fleet work', which is a parameter preference rather than usage guidance for the tool itself.

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