add_device

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

With no annotations, the description fully discloses behavior: the new device receives future messages but not historical ones, and sharing the URI grants full account access. This adds essential context beyond the schema.

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 description is brief (2-3 sentences) with no redundant information. It is well-structured, front-loading the core action and then providing usage and security details.

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 single-parameter tool with no output schema, the description is complete: it explains the input, the effect, and how to verify success via list_devices. No gaps remain.

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?

The sole parameter 'uri' has a schema description, but the tool description adds value by explaining its origin (signal-cli link or QR code). Schema coverage is 100%, so baseline is 3; the extra context justifies a 4.

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?

The description clearly states the tool's action: linking a secondary device via a device-link URI. It distinguishes from sibling tools like remove_device, making the purpose unambiguous.

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?

It explains when to use the tool (to link a new device), where to obtain the URI (signal-cli link or QR code), and provides explicit guidance on confirmation (list_devices) and alternatives (remove_device). Also includes a critical warning about not sharing the URI.

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