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

Annotations already declare readOnlyHint=false and destructiveHint=false, so the mutation/no-destruction profile is known, and the description adds the set of updatable fields on top. It does not say what happens to fields omitted from the call (preserved vs. cleared), whether the update replaces or merges, or whether the script must be idle/not running.

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 compact sentence with the verb and mutable surface front-loaded; nothing is wasted. It is arguably too terse for a 5-parameter mutation tool, but there is no filler.

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?

Fully documented schema plus annotations mean the mechanical essentials are covered, and no output schema is needed. What is missing is the partial-update contract and sibling disambiguation against update_script, both of which matter for a 5-parameter mutation tool in a crowded toolset.

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 coverage is 100% with per-parameter descriptions for code, name, script_id, and test_type, so the schema carries the semantics. The description only restates the field list and adds no format, partial-update, or validation detail beyond it, which is the baseline case.

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?

Names a specific verb and resource ('Update a k6 script') and enumerates the mutable fields (code, name, configuration). It stops short of distinguishing itself from the close sibling update_script, or from k6_create_script, so the agent must infer which updater applies to which script kind.

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?

No statement of when to use this versus update_script, k6_create_script, or k6_get_script, and no prerequisites such as needing an existing script_id from k6_list_scripts. The agent is left to infer the routing entirely from the name.

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