List compute services

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

Adds substantial context beyond the readOnly/idempotent annotations: the elevated role requirement and the crucial error semantics ('forbidden means the role is missing, not that the list is empty'), which prevents an agent from misreading an auth failure as an empty result. It also discloses the no-pagination behavior, so the agent knows a single call returns everything.

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 tight sentences with zero filler, each carrying a distinct payload (what it lists, auth/error semantics, pagination and filtering). The most decision-relevant facts come first.

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, and the description covers the non-obvious risks: permissions and forbidden-vs-empty interpretation. The only real gap is not spelling out what host and binary filter on, which would round out an otherwise complete definition.

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 50%: limit and project_id are documented in-schema, while host and binary are bare. The description's 'narrow with filters' hints at the filtering intent but never names host or binary, so the two undocumented parameters remain ambiguous. This matches the baseline 3 for a schema that does half the work.

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?

Names a specific verb and resource ('List Nova services such as nova-compute') and states the returned fields (host and state), which separates it from the volume/network service siblings. It stops short of explicitly contrasting with the similarly named list_services, so the agent must infer the OpenStack distinction.

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?

Provides useful operational guidance: 'Usually needs more than a project reader role' and 'Not paged; narrow with filters.' However, it never tells the agent when to pick this over list_services or list_volume_services, leaving the key sibling choice implicit.

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