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

Annotations already cover read-only, idempotent and non-destructive semantics, but the description adds real context: it hits a live endpoint (GET /accounts/{email}), enumerates the returned fields (tier, percentUsed, resetsAt, quotaStatus, topup*, session state), and warns that topupBalance/topupTotal are in Muse's own unit, not tokens. That unit caveat is the kind of thing annotations cannot convey.

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 verb, resource and the LIVE qualifier, then the sibling disambiguation, then the return shape. The parenthetical quoting a literal UI string ('0% used (1B tokens left)') is slightly verbose but earns its place by anchoring the unit semantics.

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?

There is no output schema, so naming the returned fields and the route (GET /accounts/{email}) is necessary and it is done well. Only minor gaps remain, such as behavior when the email is unknown or ambiguous across multiple accounts.

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% and the schema already explains that email is 'Optional when the API token has one Muse account.' The description does not add any further meaning to the parameter, so the baseline 3 applies since the schema does 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?

States a specific verb and resource ('Read one Muse account') plus its defining trait: the read is LIVE against Muse rather than the stored copy. It explicitly names the sibling muse_list_accounts as the non-live alternative, so an agent can route without opening either 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 an explicit use/avoid split: 'Each call reads Muse: muse_list_accounts shows the stored copy without a call.' This tells the agent both what this tool costs (a live call) and which sibling to pick when a cached read suffices.

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