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

With no annotations, the description carries the full burden and does so well: AES-256-GCM sealing before DB write, key never returned or logged, a read-only validation call first, and the skip_check bypass. It omits error behavior on failed checks and whether re-saving overwrites an existing key, but the disclosure is far above typical.

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?

Front-loaded with the access gate ('Pro, owner only') and then packed with provider mappings and security behavior in a few dense sentences. Every sentence earns its place with no filler.

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 9-param mutation tool with no annotations and no output schema, the description covers the critical behavioral surface: auth/tier, encryption, validation, and provider-specific inputs. Minor gaps remain around overwrite/idempotency behavior and failure modes, but an agent has enough to call it correctly.

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 already 89%, so baseline is 3; the description adds real value beyond the schema by mapping provider-specific requirements (Vercel needs team_id/project_id, Modal/Workers need bridge_url) and noting vercel is the default. It stops short of explaining skip_check's risk or make_default semantics in the prose, but clearly exceeds baseline.

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+resource ('save one provider key') and scopes it precisely against siblings delete_provider_key and list_providers. It even enumerates the provider domain, so an agent knows exactly what resource it operates on.

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 clear prerequisites ('Pro, owner only') and routes the agent to provider_setup for the bridge_url requirement. It does not explicitly state when to save vs. delete or list, but those alternatives are self-evident from the names and the tier gate is well conveyed.

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