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

Annotations already declare readOnlyHint=true, destructiveHint=false, so safety is covered. The description adds genuine value beyond them: the URL is short-lived/signed, and it enumerates the portability formats (pg_dump, mysqldump, mongodump, redis rdb). This is useful behavioral context, though it doesn't address auth/permission requirements explicitly.

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 front-loaded sentences that lead with the core action. The final sentence carries mild marketing framing ('No data lock-in') but delivers real format information, so it mostly earns its place.

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 read-only URL-generating tool with no output schema, the description explains what the caller receives (a signed URL) and how to use it. Combined with annotations covering the safety profile, an agent has enough to call it correctly; only minor auth/prerequisite detail 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 all three parameters are already documented, including ttlSeconds bounds. The description only adds the vague notion of 'short-lived' without reinforcing the parameter semantics. Baseline 3 is appropriate when the schema does the heavy lifting.

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: 'Generate a short-lived signed download URL for a backup file.' This clearly distinguishes the tool from a direct-download or in-place restore action. It doesn't explicitly name or contrast with siblings like nexusai_db_restore, so it falls short of full sibling differentiation.

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 description gives an implied use case ('download the backup and restore offline'), which contextualizes when to reach for it. However, it never states when to prefer this over nexusai_db_restore or nexusai_db_backup_list, nor any exclusions. Usage is inferred rather than spelled out.

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