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

With no annotations, the description carries the full burden and does so thoroughly: it discloses the server-side fetch/splice/write mechanism, the shared auth path and byte/depth/node-count guard, that append is non-idempotent by design with dedupe left to the caller, that @-mentions fire doc.mention_added plus inbox/email fan-out only for newly added mentions, and that editor role is required. These are exactly the traits an agent cannot infer from the schema.

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 core purpose and non-idempotency caveat are front-loaded, and the sentences are information-dense rather than padded. However, the long enumerated markdown surface (callouts, KaTeX, mermaid, embeds, mentions) is boilerplate-heavy and inflates the description well beyond what is needed to select and invoke a 3-parameter append tool.

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 no-annotation, no-output-schema mutation tool, the description covers auth requirements, side effects, event fan-out, and guard limits, which is substantial. It stops short of stating the return value or error behavior when the guard is exceeded, leaving a small gap.

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, but the description adds real meaning beyond it: it explains that markdown becomes one or more new blocks at the end, and that surface_slug selects a specific doc surface in multi-surface workspaces (omit for primary). It also documents markdown constraints such as HTTPS-only images and the 100 MB video limit, which are not in the schema.

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 target ('Append a chunk of Markdown to the END of a workspace's doc body') and explicitly scopes the tool as append-only rather than replace. This cleanly separates it from siblings update_doc and update_doc_section. An agent can tell what it does without opening the 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?

Names the intended callers ('crons + ingest agents that produce content in timestamped chunks') with concrete examples (changelog updates, daily standups, batch summaries), which is strong when-to-use context. It does not, however, state when NOT to use it or explicitly route to update_doc/update_doc_section for full-body replacement, so the alternative-selection rule is left implicit.

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