tenki_update_sandbox

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

Annotations already declare readOnlyHint=false, destructiveHint=false, and idempotentHint=false, so the agent knows this is a mutating, non-idempotent but non-destructive operation. The description adds the 'existing sandbox' constraint and 'mutable fields' scope, which is useful. However, it doesn't disclose the replacement semantics for tags (partially covered in schema) or what happens to unspecified fields (e.g., are they preserved? reset?). With annotations carrying the basic safety profile, a 3 is appropriate.

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?

A single sentence with zero waste, front-loading the purpose and listing the mutable fields. It could be slightly more structured by mentioning the session_id requirement, but the description earns its place efficiently.

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 a 5-param tool with 100% schema coverage, full annotations, and no output schema, the description is mostly adequate. It names all mutable categories with their natural-language aliases (idle timeout, max duration) which helps an agent map them to parameters. It doesn't mention response behavior, but with no output schema and a clear mutation operation, this is a minor gap.

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 documents every parameter's meaning. The description adds the breadth of mutable fields (name, tags, idle timeout, max duration) that maps to the schema, but doesn't add meaning beyond it. Baseline 3 applies since the schema does the heavy lifting.

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 states a specific verb ('Update') and resource ('existing sandbox') and enumerates the exact mutable fields (name, tags, idle timeout, max duration). This clearly distinguishes it from sibling tools like tenki_pause_sandbox or tenki_extend_sandbox, though it doesn't explicitly name them.

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 implies its use case — updating fields on an existing sandbox — but provides no explicit guidance on when to prefer this tool over alternatives like tenki_extend_sandbox, which also modifies duration. No exclusions or when-not-to-use conditions are given, leaving the agent to infer the distinction from field names.

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