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

Annotations mark this as a non-destructive, non-readOnly, closed-world write. The description adds genuinely useful context beyond that: 'No approval needed — noting your own uncertainty isn't acting on the user's behalf', which explains why an agent may write freely, plus 'the gap registry is your working memory'. It doesn't cover rate limits or response shape, but the approval-free rationale is substantive added value.

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?

Front-loaded with the core purpose and the guidance to use it liberally, then moves to required content and the subject attachment. It's appropriately sized, though the question/rationale/resolution sentences partially restate the schema, adding mild redundancy.

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 6-param create tool with no output schema, the description covers purpose, when to use, required content, subject attachment, and the approval-free behavior. It doesn't say what the call returns (e.g., the created gap id) or whether a subject requires a matching subjectType, but nothing essential for correct invocation 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 earns extra: it maps the required 'question' to a framing rule ('one clear question'), ties 'rationale' to 'what answering it unblocks', and — critically for the thin schema entries — explains subjectType/subjectId as the mechanism for tying a gap to a specific page or person. That last point adds meaning not present in the schema text.

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 and resource — 'Records something you don't yet know' against the 'gap registry' — and reframes the resource as 'open question (gap)', so an agent knows this is the create side of the compass_gaps_* family. The framing is distinguishable from compass_gaps_list/resolve/update 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?

Gives concrete when-to-use context: 'use it liberally while mapping or interviewing', and conditions the subject attachment on whether the gap is ABOUT a specific page or person. It stops short of naming alternatives explicitly (e.g., compass_gaps_update to amend, compass_gaps_resolve to close), so it's clear context but not full routing guidance.

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