mux_mount

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

With no annotations, the description carries the full behavioral burden. It goes well beyond a generic verb by disclosing idempotent upsert behavior, the absence of child processes, no URL involvement, and local-only writes. This is strong transparency for a simple mount operation, though it does not describe failure or return behavior.

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 exceptionally tight: one core sentence followed by three high-value fragments. Every phrase earns its place, and the main purpose is front-loaded. There is no filler or repetition of schema 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 low-complexity tool with two required string parameters, an output schema, and no nested objects, this description is nearly complete. It covers the operation, idempotency, scope, and side-effect profile. It could be slightly richer on what 'empty' means or what happens if the prefix already exists, but those are minor for a 2-parameter tool with an output schema.

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 the schema already explains both 'name' and 'prefix' clearly. The tool description adds context about the mount being 'empty' and 'named,' but it does not meaningfully deepen parameter-level semantics beyond the schema. Baseline 3 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 uses a specific verb ('Register') and resource ('an empty named MCP server on the in-process mux'), making the core function immediately clear. It also distinguishes itself from likely siblings like list_mounted_servers and openapi_stub by clarifying that this is an in-process mount with no child process or URL.

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 clear contextual signals about when this tool is appropriate: it registers an in-process server, is idempotent, and is local-only. It does not explicitly name alternatives or say 'use this instead of X', but the constraints ('No child process, no URL. Local write only.') effectively rule out sibling tools that might involve remote or stub-based servers.

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