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

Goes beyond the annotations (readOnlyHint=false only signals mutation) by stating that existing tokens remain valid and no re-login is required — genuinely useful post-mutation context. It does not cover failure behavior (wrong old password, mismatch of the two new entries), 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?

The core content is front-loaded and each sentence carries information (trigger, constraints, scope boundary, post-condition). The bilingual keyword tail "| EN: password, credentials, account" is retrieval padding that adds no instruction value.

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 and a simple 3-param schema, the description supplies the important behavioral envelope (own account only, tokens survive). The open gap is the mismatch between the empty `required` array and the prose calling the fields mandatory — an agent could infer optional inputs.

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%, so baseline would be 3, but the description adds cross-field semantics the schema does not express: the old password is mandatory and the new one must be supplied twice identically. Useful, though it doesn't clarify why the schema lists the fields as optional while the text calls them required.

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 the password of one's OWN account) and explicitly bounds scope to the caller's own account, distinguishing it from sibling `onto_user_update`, which it names for account administration. An agent can pick between the two without opening a 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 the triggering condition ("Nutze es, wenn der Mensch das Passwort wechseln will") and an explicit exclusion with the alternative: foreign passwords cannot be set even by an admin, accounts are managed via `onto_user_update`. That is when-to-use, when-not, and the alternative all in one.

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