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

Annotations cover the safety profile (readOnly=false, idempotent=false, destructive=false), and the description adds genuinely useful context beyond them: the write targets the customer's TestRail instance, user confirmation is required, and it returns the new attachment_id. 'This writes' is consistent with destructiveHint=false since a write is not necessarily destructive.

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?

Three compact sentences, front-loaded with the core action, followed by the precondition and the mandatory confirmation. Every sentence earns its place with 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?

Complete for a mutation tool: it covers the precondition, the required user confirmation, the target system, and the return value (attachment_id) despite there being no output schema. An agent has everything needed to invoke it correctly.

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%, so the schema already documents all three parameters including the workspace path format and displayFilename override. The description reinforces that the file must exist but adds no syntax or format detail beyond the schema, so baseline 3 applies.

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?

States a specific verb (attach) plus resource (file to a TestRail case) and scope (from the /workspace path). The name and description together clearly distinguish it from siblings like testrail_get_attachment and testrail_list_attachments.

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?

Provides strong preconditions: the file must already exist at the workspace path and must be written first if needed. It also mandates confirming with the user before calling. It does not name sibling alternatives, but the when-to-use context is otherwise explicit.

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