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

Annotations already declare readOnlyHint=false, idempotentHint=true, and destructiveHint=false. The description adds the partial-update behavioral trait (only provided fields are changed), which is valuable. However, it does not disclose other behaviors like validation failures, missing package handling, or atomicity, so it remains at the level expected given annotation coverage.

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 precisely two short sentences: 'Update an existing service package. Pass only the fields you want to change.' Every word earns its place, with no redundancy or 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?

The tool has 9 parameters, but the input schema covers all of them with descriptions, an output schema exists, and annotations provide safety details. The partial-update instruction is the key contextual gap-filler and is present. Missing details like cross-field dependencies (e.g., applicableItems vs applicableType) are not in the description, but the schema descriptions also do not cover them, so the description meets a sufficient bar for complex update tools.

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%, with all 9 parameters having descriptions in the input schema. The description itself adds no parameter-level detail beyond the general partial-update hint; the schema carries the full semantic load for parameters.

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 'Update an existing service package' with a specific verb ('Update') and resource ('service package'). The word 'existing' differentiates it from create_service_package, and the verb distinguishes it from delete/restore/list sibling tools.

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 instruction 'Pass only the fields you want to change' provides clear partial-update usage guidance, and 'existing' implies this tool is for modifying already-created packages rather than creating new ones. It does not explicitly name alternatives, but the context is clear.

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