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

Goes well beyond annotations: password is shown exactly once and must be treated as a secret, propagation is 'within seconds', a 30-user limit applies, and it details the exact privileges granted (read/write + table creation, public schema on PostgreSQL, SELECT-only with read_only, no access anywhere else). Also documents the connection_uri target and the Valkey-specific degradation, none of which annotations 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?

The critical facts (created user, one-time password) are front-loaded, but the body is a single dense paragraph with stacked parentheticals ('(on PostgreSQL in public too)', '(no databases, no read_only)') that could be split into scannable points. Every sentence carries information, but the structure makes it harder to extract than it needs to be.

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?

For a mutating, credential-generating, platform-varying operation with no output schema, the description covers creation effects, secret handling, limits, per-engine behavior, and required scope. An agent has everything needed to call it and to warn the caller about the one-time password.

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 the baseline is 3; the description adds real meaning by explaining the consequence of omitting databases (all logical databases, future ones included) and of read_only (SELECT only, MySQL/MariaDB SELECT+SHOW VIEW), plus where the resulting connection_uri points. Some of this duplicates the schema's own parameter text, keeping it below 5.

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?

Opens with a specific verb+resource+effect: 'Creates a user with a generated password, returned here once.' This clearly separates it from delete_database_user and get_database_credentials without needing the 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?

Points to get_database_credentials as the alternative for reading the password later, and states the scope requirement (databases.write) and the 30-user cap. It doesn't explicitly say when to use set_database_user_access instead of the databases/read_only parameters at creation time, so it falls short of a full when/when-not statement.

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