session_show_defaults

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

No annotations are provided, so the description carries the safety/behavior disclosure burden. It adds the behavioral context of being a required precursor and warns against assuming defaults are set, but does not explicitly state that it is read-only or describe possible side effects, which is a gap given the absence of 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 two sentences, front-loaded with the primary purpose, and includes essential prerequisite context without any fluff. The 'XcodeBuildMCP' prefix is minor noise but does not detract from overall conciseness.

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?

Given the tool's simplicity (no params, no output schema) and the clear action, the description covers the essential context. The added note about being required before first build/run/test calls provides valuable operational context, making it reasonably complete for its intended use.

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 tool has zero parameters and 100% schema coverage (empty schema). Per rubric, baseline is 4 when no parameters exist; the description correctly adds no redundant parameter details, so this score is appropriate.

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 with a specific verb+resource: 'Show current active defaults.' It distinguishes itself from sibling tools like 'session_set_defaults' by indicating this is the read/display counterpart, making its 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?

The description gives explicit when-to-use guidance: 'Required before your first build/run/test call in a session.' It does not explicitly mention alternatives, but the prerequisite context is clear and actionable, which is sufficient for a 4.

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