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

Annotations already declare the mutation profile (readOnly=false, idempotent=true, destructive=true), and the description adds real context on top: sparse/partial-update semantics, the Plus tier gate on daily frequency, and the connected-account auth model with no extra sign-in. It does not explain why the tool is flagged destructive or what a toggle-off affects, which keeps it at a 4 rather than 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?

Four short sentences, front-loaded with the action, and each carries a distinct fact (partial update, tier gate, auth). The frequency sentence mildly duplicates the enum description in the schema, a minor 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?

With no output schema, the description covers the essentials for an eight-flag optional mutation: partial-update behavior, a tier constraint, and auth requirements. It omits what the call returns or any error behavior, but nothing critical to correct invocation 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 the schema already documents all eight optional flags and the daily/weekly enum. The description largely restates the frequency constraint rather than adding new per-parameter meaning, so the 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 (turn on/off) and resource (Himalayas emails) for the connected user, which is distinct from the account/profile-oriented siblings like update_account and update_profile. It does not explicitly name a sibling it must not be confused with, so it falls short of a 5.

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?

"Only the settings you pass change" gives useful partial-update guidance and the Plus/weekly note constrains the frequency choice, so usage is implied and reasonably clear. However, there is no explicit when-to-use vs. when-not, and no routing against the many update_* siblings.

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