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

Annotations already cover readOnly/non-destructive/closed-world, and the description adds real context on top: it discloses the exact read scope (name and email) and explicitly bounds what is not exposed (private passages, saved words), which matters for an agent reasoning about data exposure. It stops short of describing failure behavior when no account is connected.

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 short sentences, front-loaded with the action and followed by prerequisite and scope exclusions; no filler. 'before saving' is the only slightly opaque fragment.

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 carries the return-value burden and does so by naming the returned fields. Combined with the prerequisite and scope exclusions, an agent has enough to call it correctly; only the not-connected error case is unaddressed.

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?

The tool takes zero parameters, so there is nothing for the description to disambiguate; the baseline applies. The description correctly signals a no-argument, single-object read.

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 ('Show the connected MTW account') and names the exact fields returned (account name and email). It is clearly distinguishable from the word-level siblings (inspect/read/save_mandarin_word), though the abbreviation 'MTW' is only expanded in the title, not the description.

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 phrase 'before saving' implies a pre-flight check ahead of save_mandarin_word, and 'Requires account connection' gives a prerequisite. However, it never names the sibling explicitly or states when not to call it, leaving the routing inference to the agent.

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