switch_account

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

Adds substantial behavioral context beyond the annotations: it re-points the token file, drops the previous account's cached reads and validators, requests confirmation first, and refuses during in-flight requests. Critically, it resolves the ambiguity of destructiveHint=true by clarifying no Spotify writes are issued — a genuinely valuable distinction.

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?

Front-loaded with the core action, then layers effect, mechanics, and safety in dense, non-redundant sentences. It is on the longer side, but nearly every clause carries operational information an agent needs before switching accounts.

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 session-state-mutating tool with no output schema, the description covers scope of effect, prerequisite auth state, cache invalidation, concurrency behavior, and confirmation handling. Nothing an agent needs to call it safely is missing.

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 100%, so both the profile parameter and its auth prerequisite, plus the response_format enum, are fully documented in the schema. The description adds no parameter-level syntax or constraints beyond that, so baseline 3 applies.

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 — 'Change which registered account this session acts as' — and scopes it to the session, which cleanly separates it from list_accounts and other account-adjacent siblings. An agent can act on it without opening the schema.

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 clear context for when the tool applies (every subsequent call in the session, requires prior 'spotify-mcp auth --profile <name>') and a guard condition (refuses while a request is in flight). It stops short of naming an alternative sibling or an explicit 'don't use this when...' rule, so it lands at 4.

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