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

Annotations already declare readOnlyHint=false, idempotentHint=true, and destructiveHint=false, and the description does not contradict them. Beyond annotations, the description contributes only 'privacy-filtered project metadata,' which is more about input handling than behavior; it does not disclose what the 'sent' transition entails, failure modes, or the concurrency implications of expectedVersion.

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?

The description is a single short sentence and is economical, but its phrasing ('Update hosted relay mark sent') is syntactically awkward, and the brevity sacrifices substance. For a tool with a nested object and 7 parameters, the text under-specifies rather than being truly concise.

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?

This is a 7-parameter mutation tool with a nested details object, a required idempotencyKey, an expectedVersion optimistic-concurrency check, and no output schema. The description explains none of the key semantics an agent needs: what 'mark sent' does, what handoffId refers to, how expectedVersion conflicts are handled, or what data the details object should carry.

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 0%, so the description carries the full burden for parameter meaning, but it names none of the 7 fields (projectId, handoffId, idempotencyKey, expectedVersion, details, sessionId, executionId). The phrase 'privacy-filtered project metadata' is a weak nod toward projectId/handoffId but says nothing about idempotencyKey, expectedVersion, or the nested details object.

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 an action on a specific resource ('Update hosted relay mark sent'), which distinguishes it in a general sense from read-style relay siblings like relay_status and relay_poll. However, the phrase 'mark sent' largely rephrases the tool name without defining what is actually being marked, and no explicit sibling differentiation is provided. The purpose remains vague enough that an agent cannot tell exactly what state transition occurs.

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?

No guidance is given for when to use this tool versus the many relay siblings (relay_accept, relay_dismiss, relay_poll, relay_release, relay_sync_completion, relay_status). The required handoffId and expectedVersion imply a sequencing or handoff lifecycle, but the description neither states preconditions nor contrasts this tool with alternatives.

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