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

Annotations already cover core behaviors like being readOnly and idempotent. The description adds valuable operational context (that it is called by the UI widgets and shows the newest projects with a cover), which aids selection but does not provide complex behavioral constraints missing from the annotations.

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 highly efficient, front-loading the tool's primary function in the first sentence and the usage guidance/sibling differentiation in the second. Every word is purposeful.

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?

The tool involves UI interaction (sidebar/widget). Describing this context and contrasting its function with the listing sibling makes the definition extremely complete for an AI agent determining how to trigger a specific visual output.

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?

With 100% schema coverage, the schema adequately describes the 'locale' parameter. The description confirms its semantic role as the host's BCP 47 locale, which meets the baseline requirement for a fully covered schema.

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 function: to display the workspace's newest projects within a specific UI context (sidebar/widget). It successfully distinguishes this presentation role from the enumeration role of the sibling tool, list_projects.

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 provides explicit usage guidelines by defining the condition for using the alternative tool. The instruction 'To list projects yourself, use list_projects' leaves no room for ambiguity regarding the tool's intended application.

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