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

Goes well beyond the annotations (which only declare readOnly=false, destructive=false, openWorld=false). It discloses the exact set of fields a PUT resets when omitted (flags, lock, from_description, subsystem_id, source_story_ids, source_requirement_ids), the merge-by-key semantics, and the lifecycle/implementation_status interaction. This is precisely the destructive-ish behavior context an agent needs and that annotations cannot convey.

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?

Four dense sentences, purpose front-loaded, each carrying non-redundant information. The clause about lifecycle and implementation_status is long but earns its place; overall tight, if slightly compressed for readability.

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 nested, 3-param mutation tool with an output schema present, the description covers the critical unknowns: merge vs replace semantics, which fields are reset, and which sibling to prefer. Return values need not be explained given the output schema, so nothing essential is missing.

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 genuine semantic value: that content merges by key, that arrays should be used for metadata, and which top-level fields reset on omission versus persist. It does not restate every content field, but the merge/reset rules are the meaning the schema alone doesn't give.

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 (update) and resource (a requirement), and positions it against the sibling requirements_patch. However it does not restate the UUID-based selection in prose; the reader must infer 'a requirement' is selected by requirement_id, and the PUT-vs-merge distinction is only implied through the reset rules.

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?

Explicitly names the alternative: 'Prefer requirements_patch for partial edits,' which effectively tells the agent when-not to use this tool. It doesn't spell out an affirmative when-to-use (e.g. 'use for full replacement/flag resets'), leaving that to inference, so it stops short of a 5.

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