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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), so credit goes to the added context: 'no call to Mureka' tells the agent this reads cached useapi.net state rather than fetching live data, which matters for freshness. It still does not mention staleness timing or pagination/size limits, so not a full 5.

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 clauses: what it reads, why to use it (with alternatives), and the underlying route. Scope is front-loaded and there is no filler.

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, and the description compensates by naming the returned fields (sign-in mode, token expiry, sign-in error). Combined with the sibling routing and the cached-data caveat, an agent has everything needed to call it correctly.

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% with a single parameter whose meaning and provenance ('from mureka_list_accounts') are fully documented. The description only implies the account selector via the 'GET /accounts/{account}' route and adds no format or syntax detail, so baseline 3 is appropriate.

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 ('Read one Mureka account as useapi.net stores it') and enumerates exactly what it returns: sign-in mode, session token expiry, and sign-in error. It explicitly distinguishes itself from mureka_list_accounts and mureka_get_profile, so an agent can select it without opening the schemas.

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 trigger ('Use it to see why an account fails') and names two alternatives with their distinct scopes — mureka_list_accounts for every account, mureka_get_profile for live plan and Gold. This is a clean when-to-use plus when-to-use-something-else.

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