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

With no annotations, the description carries the disclosure burden and does well: it declares the write is an append-only event, names the source-of-truth record ('evidence.attached' on 'run:{id}'), and states the supersede behavior of a second attach to the same slot. It omits auth/permission requirements and any failure modes, keeping it below a 5.

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 action and followed by mechanics and routing advice; each sentence carries distinct information. Minor density from internal terms like 'evidence.attached' and 'run:{id}', but nothing is redundant.

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 9-parameter mutation tool with an output schema and no annotations, the description covers the essential mechanics (append-only, source of truth, supersede, preferred alternative). What remains missing is permission/authorization context and error behavior, which leaves a small but real 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 coverage is 100%, so the baseline is 3, but the description adds semantics beyond the schema by explaining that a second attach to the same slot supersedes the prior pointer, which clarifies the interplay of 'slot' and 'supersedes'. It does not elaborate on 'kind' inference or 'pointer' formats beyond what the schema already documents.

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 first sentence states a specific verb and resource ('Attach evidence to a Process run') plus the mechanism ('via an append-only event'), which distinguishes it from evidence_get, evidence_require, file_create, and storage_attach. An agent can tell what it does without opening the schema.

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?

It explicitly names preferred alternatives ('prefer this (or file_create(work_id=) auto-attach) over mutating a case-file row'), giving real routing guidance against a named anti-pattern. It stops short of saying when to call evidence_require or evidence_get instead, so no explicit exclusions are stated.

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