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

Annotations already declare destructiveHint=true, readOnlyHint=false and idempotentHint=false. The description goes well beyond them: it requires 'write' scope, guarantees the full text is never overwritten, mandates that each search find EXACTLY one occurrence, and states the call is refused (not-found/ambiguous) rather than guessed. Those are precisely the failure modes an agent must anticipate.

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 purpose, then ordered constraints (scope, matching rule, append rule, fallback routing). Every sentence carries distinct operational information with no filler.

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 destructive 1-parameter mutation tool whose annotations already cover the safety profile, the description supplies the remaining essentials: scope requirement, non-overwrite guarantee, exact-match rule, append behavior, and where to go when no match exists. No output schema is needed to complete it.

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. The description adds real meaning: operations run in order, an operation's 'search' must match exactly once, and an operation without 'search' is appended to the end. That clarifies matching and append semantics beyond the field descriptions.

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 concrete verb and resource: applies search/replace or append operations on the organization's custom_instructions text. It distinguishes itself from ficiel_edit_agent_profile by noting that structured-profile settings (e.g. tutoiement/vouvoiement) are NOT edited here, so an agent can route correctly without opening either 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 clear when (search/replace on free-text instructions) and when-not (settings that live in the structured profile belong to a different mechanism/Ficiel configuration). It doesn't name ficiel_edit_agent_profile directly, leaving the alternative tool implicit, but the routing context is explicit and actionable.

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