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

The description goes beyond the annotations by disclosing membership validation, error surfacing (NOT_A_MEMBER / SPACE_NOT_FOUND as isError), idempotency, and the global side effect of affecting subsequent calls. This is rich behavioral detail that the readOnlyHint/destructiveHint annotations do not capture.

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 description is three sentences, front-loaded with the core action, and each sentence earns its place by adding essential context (scope, validation, idempotency). No fluff or redundancy.

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 single-parameter setter with no output schema, the description fully covers the purpose, side effects, error behavior, and idempotency. It is complete enough for an agent to use correctly without additional context.

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 100% with a detailed description of space_id, so the tool description does not need to explain it. However, the schema's parameter description says 'Override the active Space for this one call,' which conflicts with the tool's purpose of persistently setting the active Space. The tool description does not correct this ambiguity, so it misses an opportunity to add clarity.

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 uses a specific verb ('Switch') and resource ('active Space') and clearly differentiates from siblings like get_active_space and list_spaces by explaining that subsequent tool calls are scoped to the chosen Space. This precisely states what the tool does.

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?

The description explicitly explains when to use it ('Subsequent tool calls... are scoped to the chosen Space'), which gives clear context for setting the active Space. It does not explicitly mention alternatives such as passing space_id per call, but the schema's parameter description covers that, so the lack of exclusion is a minor gap.

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