login_instance

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

No annotations provided, so description carries full burden. Discloses session caching and token expiration. However, lacks details on error handling, permissions, or any destructive potential. The behavior is straightforward for a login tool, but more transparency could improve safety.

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?

Well-structured with clear sections and bullet-style arg list. Every sentence adds value: prerequisite, caching, param descriptions, return. Slightly verbose but not wasteful.

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?

Covers all essential aspects: prerequisite, caching, all parameters, return value. Output schema exists so return detail is sufficient. For a login tool, it is complete and actionable.

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 0%, so description fully compensates. Each parameter is explained with examples, defaults, and context (e.g., instance_id format, db_type values, region default). Adds meaning beyond schema significantly.

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?

Clearly states 'Login to a database instance via Tencent Cloud DMC' with specific verb and resource. Distinguishes from sibling tools by mentioning find_instance_by_ip as a prerequisite and specifying supported database types (TDSQL-C and TDSQL).

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?

Provides explicit context: use after find_instance_by_ip to get instance_id and db_type. Mentions session caching and token reuse. Does not explicitly state when not to use, but the guidance is clear enough for correct tool selection.

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