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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered by structured data. The description adds only the trigger condition; it says nothing about that results are chunked via max_characters/cursor pagination or that a guide may be returned by task-matching, both of which are behavioral traits the schema alone implies rather than states.

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?

A single front-loaded sentence with no filler, which is structurally sound. It is terse to the point of being under-specified rather than wasteful, so it earns a 4 rather than a 5.

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?

An output schema exists, so return-shape explanation is not owed, and 100% param coverage means the schema carries the argument burden. Still, for a 6-parameter, paginated, single-optional-id fetch/list tool, the description leaves the core mental model (what a Locus guide is, when to prefer this over describe_api) unstated.

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 100% and all six parameters carry their own descriptions, so the baseline is 3. The description adds no meaning beyond that — it does not even hint at the list-vs-fetch duality (omit id to list, supply task to pick) which is the tool's most important parameter interaction.

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?

"Fetch Locus guides" gives a clear verb plus resource, and the qualifier "when native skills are unavailable" scopes it. However, "Locus guides" and "native skills" are never defined, so an agent unfamiliar with the platform cannot tell what content is actually returned or how this differs from documentation-oriented siblings like describe_api.

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 phrase "when native skills are unavailable" is a genuine usage condition, but it is the only one and is never unpacked — there is no statement of what "native skills" means, no fallback ordering, and no alternative tool named for the case where a skill is available.

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