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

Beyond the annotations (readOnlyHint=false, idempotentHint=true, openWorldHint=true), the description adds meaningful context: the effect is broadcast to other editors, a stale revision will break it, and surrogate pairs cannot be split. It stops short of describing failure behavior or what other participants observe.

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 short sentences, each carrying distinct information, with the effect stated first and constraints after. Slightly elliptical phrasing ('this MCP participant's') costs a little clarity but nothing is wasted.

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 four-required-parameter, no-output-schema tool the description covers effect, encoding, and revision precondition, but omits what anchor vs head mean, how the revision is obtained, and what happens on a stale-revision rejection. Adequate but with clear gaps.

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 0%, so the description must carry the parameter burden. It clarifies that anchor/head are UTF-16 offsets rather than byte offsets, which is valuable, but it never distinguishes anchor from head (selection direction) and leaves 'path' and the 64-hex 'expectedRevision' format unexplained.

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 description states a concrete action and effect: it surfaces this participant's selection to other editors, which is more specific than the tool name 'crabrix_select'. It is clearly distinguishable from write-oriented siblings like crabrix_apply_changes, though it never names an alternative explicitly.

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?

'Requires the latest project revision' is a real precondition that tells the agent when the call will succeed, but there is no guidance on how to obtain that revision (e.g., via crabrix_status) or when to prefer this over other presence/collaboration tools. Usage is implied rather than spelled out.

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