update_invoice

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

With no annotations provided, the description carries full burden for behavioral disclosure but fails entirely. It doesn't indicate that this is a mutation operation, what permissions might be required, whether updates are reversible, potential side effects, or error conditions. The vague 'Update' gives no insight into actual behavior beyond the basic action implied by the name.

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 extremely concise at just three words, which could be appropriate if it were more informative. However, this brevity results in under-specification rather than efficient communication. While front-loaded, it lacks the substance needed to be truly helpful.

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 mutation tool with 2 parameters (including a nested object), 0% schema coverage, no annotations, and no output schema, the description is completely inadequate. It provides no information about what the tool actually does, how to use it properly, what it returns, or any behavioral characteristics. This leaves critical gaps for agent understanding.

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 0%, meaning neither parameter (invoice_id, data) has any documentation in the schema. The description adds no parameter information whatsoever - it doesn't explain what invoice_id should contain, what fields can be in the data object, or any constraints. This leaves both parameters completely undocumented.

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 'Update an invoice' is a tautology that merely restates the tool name without adding specificity. It lacks details about what aspects of an invoice can be updated or how this differs from other update tools like update_hours or update_project. While it identifies the resource (invoice), it provides no meaningful verb elaboration beyond the obvious.

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 offers no guidance on when to use this tool versus alternatives. It doesn't mention prerequisites (e.g., needing an existing invoice_id), differentiate from sibling tools like create_invoice or get_invoice, or specify appropriate contexts. This leaves the agent with no usage direction beyond the tool name.

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