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

With no annotations provided, the description carries the full burden. It discloses that this is a primary write operation and that agent_id must always be passed (a session/auth requirement), but says nothing about reversibility, permissions, error behavior, or whether writes are visible to others. Adequate but incomplete for an unannotated mutation tool.

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 dense paragraph, front-loaded with 'PRIMARY: Write back to the graph' followed by the sibling replacement and per-mode parameter lists. Efficient, though the run-on mode enumeration is slightly harder to scan than a list would be.

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 an 11-parameter, unannotated, no-output-schema mutation tool, the description covers the mode-conditional parameters and the required agent_id but omits failure modes, side effects, and visibility of writes. Sufficient to invoke correctly, thin on operational context.

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 every schema property already carries a 'For trace/crossing/message:' description, so the description's mode-to-parameter mapping largely restates the schema. Baseline 3 is appropriate; it adds the conditional grouping but no new meaning beyond the structured fields.

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 ('Write back to the graph') and immediately distinguishes itself from siblings by naming the three tools it replaces (record_trace, save_crossing, post_message). An agent can tell exactly what this does and which siblings it supersedes without opening any 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?

The description routes usage by enumerating the three content_type modes and the parameters each mode requires, which tells the agent which mode to pick and what to supply. It does not explicitly state when not to use this tool versus the legacy siblings, but the 'unified replacement' framing gives clear context.

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