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

No annotations are provided, so the description carries the full burden; it does disclose the return content ('list of relevant subreddits with descriptions'), which is genuinely useful. It says nothing about whether the call is read-only, whether it needs authentication, pagination behavior, or how results are ranked, all of which matter for a discovery tool with zero annotation coverage.

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, front-loaded with the core action and resource, and the return value is stated before the usage hint. The final sentence ('Useful for finding niche communities...') partially restates the opening, keeping it just shy of a 5.

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 two-parameter, zero-required discovery tool this is close to adequate, and the description does sketch the return value in lieu of an output schema. The absence of any annotation coverage means the read-only/safety profile and ranking or pagination behavior are left entirely unstated, which is a real gap for an agent deciding whether to call 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 description coverage is 100%, including examples for 'topic' and bounds for 'limit', so the baseline is 3. The description adds only the framing that grouping is by 'topic or interest area', which marginally reinforces the topic parameter but adds no syntax, defaults, or edge-case semantics beyond 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?

The description uses a specific verb ('Discover') on a specific resource ('Reddit communities grouped by topic or interest area') and even states the return shape ('a list of relevant subreddits with descriptions'). It does not, however, name or contrast itself with the obvious sibling search_communities, so an agent must infer the distinction from the description alone.

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?

Usage is only implied by 'Useful for finding niche communities related to a subject' — there is no explicit when-to-use statement, no exclusions, and no named alternative such as search_communities for keyword-based lookup. An agent can guess the intent but gets no routing rules.

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

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

No annotations are supplied, so the description carries the full disclosure burden, and it does add real value by saying the response includes parent context and replies — a tree-shaped return, not a bare comment. It says nothing about authentication, rate limits, or what happens when the permalink targets a deleted or removed comment.

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?

Two sentences, front-loaded with the operation, then the rationale. The second sentence is largely implied by the first and repeats "context," but it is short enough that the redundancy costs little.

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 two-parameter read tool with no output schema, the description covers what is fetched, by what key, and roughly what comes back. The remaining gap is the return shape's granularity, which the absent output schema forces the agent to discover at call time.

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%, and the schema itself documents the 0–8 bound on context, so the baseline applies. The description adds only a loose mapping between "parent context" and the context parameter, with no explanation of how context interacts with the already-included replies.

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?

"Fetch a single Reddit comment by its permalink URL" gives a specific verb, resource, and access key, and "single" implicitly separates it from the listing sibling get_user_comments. It stops short of naming an alternative explicitly, so an agent must infer the boundary with get_post or resolve_url_type rather than being told.

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?

"Useful for getting the full context of a specific comment" hints at the use case but never states preconditions or exclusions. Nothing tells the agent when to prefer resolve_url_type for an unfamiliar URL, or when a post-level fetch is the better call.

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

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

No annotations are provided, so the description carries the full behavioral burden. It usefully discloses what data is returned and implies a read-only lookup, but says nothing about auth requirements, behavior for private/banned/nonexistent subreddits, or rate limits. For a simple read tool this is acceptable but not rich.

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?

Two tight sentences: the first front-loads what is returned, the second gives the use case. Every clause earns its place with no redundant restatement of the tool name.

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 single-parameter read tool with no output schema, enumerating the returned fields is exactly the right compensation. Only edge-case behavior (invalid or private subreddit handling) is left unstated, a minor 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?

With only one parameter at 100% schema description coverage, the schema already documents the 'subreddit' argument and its format requirement (no r/ prefix). The description adds no additional meaning about the parameter, so the baseline of 3 applies.

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 opens with a specific verb and resource ('Get metadata about a subreddit') and enumerates the fields returned (description, subscriber count, active users, creation date, NSFW flag, icon, banner), making the purpose unambiguous. It is clearly distinct from siblings like get_community_posts or search_communities by virtue of being metadata-only, though it never names those siblings 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?

'Use to evaluate or describe a community' gives a contextual hint for when the tool is appropriate, but there are no exclusions or named alternatives (e.g., use get_community_posts for content, search_communities for discovery). Usage is therefore implied rather than specified.

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

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

No annotations are supplied, so the description carries the full behavioral burden; it partially discharges this by disclosing the return payload (scores, comment counts, metadata) and the absence of prior auth discussion. It omits pagination behavior, default sort, and rate-limit or access constraints, which matter for an unannotated read 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?

Three short sentences with the core purpose front-loaded and no wasted clauses. The sort enumeration partially duplicates the schema enum, a minor redundancy.

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?

With no output schema, the description usefully sketches the return shape, and it correctly identifies the resource scope for a moderately complex five-parameter tool. Remaining gaps (default sort, page-size behavior) are largely covered by the schema itself.

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%, so the enum values, limit bounds, and pagination cursor semantics are already documented. The description only restates the available sort values and adds no meaning for 'time', 'after', or 'limit' beyond the schema, so baseline 3 applies.

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 ('Get posts') scoped to 'any public subreddit', which implicitly separates it from siblings like get_user_posts or get_popular. It does not explicitly name a sibling alternative, keeping it just short of a 5.

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?

Usage is implied by the 'any public subreddit' scoping, which tells the agent this is for public community feeds rather than user or search endpoints. There is no explicit when-to-use/when-not guidance or named alternatives among the many sibling listing tools.

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

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

No annotations exist, so the description must carry the behavioral burden, and it does give partial value by disclosing the return payload shape (names, subscriber counts, growth metrics). However, it omits ranking/ordering logic for the leaderboard, whether results are paginated by cursor in practice beyond the schema hint, and any auth or rate-limit constraints, leaving meaningful behavioral gaps.

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?

Two tight sentences with zero filler, front-loading the resource and following with the return contents. Every sentence earns its place by contributing either purpose or output information.

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 simple read-only, two-parameter listing tool with full schema coverage, the description covers purpose and return values adequately, and no output schema is needed given the explicit field list. The only gap is the absence of sibling differentiation and any note on result ordering, which are minor for this complexity level.

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%, with both 'after' and 'limit' fully documented in the schema including ranges and cursor format, so the baseline is 3. The description adds no additional meaning about pagination or limit semantics beyond what the schema already supplies.

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 names a specific verb and resource ('Get a leaderboard of trending and fast-growing Reddit communities') and enumerates the returned fields (subreddit names, subscriber counts, growth metrics), so the agent knows exactly what the tool produces. It does not explicitly distinguish itself from close siblings like get_popular or explore, which also surface community listings, leaving some ambiguity for selection.

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?

Usage is only implied: 'trending and fast-growing' suggests discovery-oriented browsing, but the description never states when to prefer this over get_popular, explore, or search_communities. No prerequisites, exclusions, or alternative-routing guidance is provided, so the agent must infer the choice from the name alone.

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

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

Since there are no annotations, the description carries the full burden. It explicitly states the data structure and content returned, listing 'titles, scores, subreddits, and comment counts,' which is critical behavioral context for an agent.

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 definition is a single, highly efficient sentence that gets straight to the point, avoiding unnecessary phrasing.

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?

Given the clear input schema and defined parameters, the description is complete enough. It adds vital context regarding the nature of the returned data (e.g., scores, comments) which guides the user experience.

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%, so the schema fully documents the parameters. The description adds no specific meaning or constraints beyond the structured data provided.

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 clearly identifies the resource (r/popular feed) and the function (trending posts), making the purpose clear. It is distinct from other retrieval tools by specifying 'current' trending status.

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?

Usage is implied: when a user wants to see general trending posts. However, it does not explicitly state when to use it versus more specific sibling tools like `get_leaderboard` or `explore`.

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

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

No annotations are supplied, so the description carries the full burden. It discloses the shape and depth of what is returned (full body, nested comment tree), which implies a read operation, but says nothing about authentication, rate limits, behavior on invalid or non-post URLs, or whether results are truncated by depth/limit.

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?

Two tight sentences, with the capability statement front-loaded and the input-format note second. Nothing is wasted, though the URL example is largely redundant with the schema's format: uri plus description.

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?

There is no output schema, so the description must convey return values, and it does by naming body text, score, flair, and the nested comment tree. For a read-only fetch tool this is close to complete; only the depth/limit truncation behavior remains unstated.

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 schema already documents url, commentDepth, and commentLimit with defaults and bounds. The description only restates the URL format with an example and adds no meaning about how commentDepth and commentLimit interact or what truncation looks like, so the baseline of 3 applies.

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 uses a specific verb (Fetch) and resource (a full Reddit post) and enumerates what comes back: body text, score, flair, and the entire nested comment tree. That return-content detail clearly separates it from list-style siblings like get_community_posts or get_user_posts, though it never explicitly names an alternative.

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?

Usage is only implied: 'Use a direct Reddit post URL' states an input-format precondition, not a when-to-use rule. There is no guidance on when to prefer this over get_comment_permalink, resolve_url_type, or get_community_posts, and no when-not conditions.

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

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

With no annotations supplied, the description carries the full burden; it does disclose the return shape (body, score, subreddit, parent post title, timestamps), which is genuinely useful since there is no output schema. However it says nothing about pagination depth, result caps, behavior for nonexistent or suspended users, or whether private accounts return empty results.

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?

Two sentences, front-loaded with the action, then the return fields, then the use case. Nothing is wasted, though the second sentence is soft filler compared to the specificity of the first.

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 simple four-parameter read tool with full schema coverage and no annotations, the description covers what it does and what comes back. The remaining gap is pagination behavior, which the 'after' parameter documents only partially.

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%, so all four parameters including the sort enum and the 'after' cursor are already documented in the schema. The description adds no additional meaning about sorting semantics or pagination behavior beyond that, so the baseline 3 applies.

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 specific verb and resource ('Get comment history for a Reddit user'), which inherently separates it from siblings like get_user_posts and get_user_profile. It does not name those siblings explicitly, so the differentiation relies on the reader inferring 'comments' vs 'posts'.

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?

'Useful for understanding a user's opinions and activity' hints at a use case but gives no when-to-use versus when-to-use-an-alternative guidance, no exclusions, and no mention of when get_user_posts or search would be a better fit.

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

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

No annotations are provided, so the description carries the full disclosure burden. It usefully lists the returned fields (titles, scores, subreddits, timestamps) in lieu of an output schema, but says nothing about pagination semantics despite an 'after' cursor parameter, no result caps beyond the schema, no rate-limit or auth expectations, and no note that this is a read-only call.

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 with no waste: purpose first, then return payload, then use case. The ordering is front-loaded and every sentence contributes distinct information.

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 4-parameter read tool with no annotations and no output schema, the description covers purpose and return fields, which is the most important gap it could fill. However, pagination behavior and sort defaults remain undisclosed anywhere outside the schema, leaving the definition adequate but not complete.

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%, so sort, after, limit, and username are already documented in the input schema. The description adds no parameter-level meaning such as a default sort order or how the pagination cursor chains across pages. Baseline 3 is appropriate when the schema does the work.

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: 'Get all posts submitted by a Reddit user.' The phrase 'submitted by a Reddit user' implicitly separates it from get_community_posts and get_user_comments, so an agent can pick correctly without opening schemas. It stops short of explicitly naming those siblings, which keeps it at 4 rather than 5.

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?

'Useful for profiling an account's posting behavior' gives a positive use case, so usage is implied rather than left blank. There is no when-not guidance, no mention of when to prefer get_user_comments, get_user_profile, or search, and no note about behavior for nonexistent or suspended accounts.

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

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

With no annotations, the description carries the full burden. It usefully discloses that only public data is returned and enumerates the payload fields, but says nothing about auth requirements, error behavior for nonexistent or suspended accounts, or rate limits. It conveys read-only character implicitly through "public profile" rather than explicitly.

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?

Two short sentences, front-loaded with purpose and followed by scope. Every clause carries information; nothing is padded or redundant.

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 single-parameter read tool with no output schema, the field enumeration effectively stands in for a return-value description, which covers the biggest gap. The remaining shortfall is error and auth behavior, which is minor for a simple public lookup.

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% and the schema itself documents that the username excludes the u/ prefix. The description adds no parameter-level meaning beyond that, so the baseline of 3 is appropriate for a single fully-documented parameter.

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 gives a specific verb and resource ("Get a Reddit user's public profile") and enumerates the profile content (karma breakdown, bio, account age, avatar, trophies, gold status), which implicitly separates it from content-oriented siblings like get_user_posts and get_user_comments. It never explicitly names those siblings, so differentiation is inferential rather than stated.

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?

There is no when-to-use guidance, no mention of alternatives such as search_users when the username is unknown, and no exclusions. "Works for any public Reddit account" is a scope statement rather than usage direction, leaving the agent to infer routing entirely.

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

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

No annotations exist, so the description must carry the behavioral load. It does disclose the output shape (detected type plus extracted identifiers such as post ID, username, subreddit), but says nothing about what happens for non-Reddit or malformed URLs, whether any network call occurs, or whether detection is purely local string parsing.

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?

Two tight sentences, outcome and enumeration front-loaded, with the usage hint last. Nothing is repeated from the schema and no sentence is 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 single-parameter classifier with no output schema, the description adequately covers both input expectations and return content. The one gap is failure behavior for unsupported URLs, which an agent would want to know before branching on the result.

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% and the single parameter is already documented as 'Any Reddit URL to classify.' The description still adds real meaning by implying the full breadth of accepted URL forms (post, comment, profile, subreddit, search links), which tells the agent it need not normalize input first.

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 ('Detect') and resource ('a Reddit URL'), then enumerates the exact classes it can resolve — post, comment, user profile, subreddit, search — and names the return payload. This clearly separates it from the retrieval siblings like get_post or get_user_profile.

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 the operative context: 'Useful before deciding which tool to call next,' which frames it as a routing/dispatch step ahead of the other tools. It stops short of naming specific alternatives or stating when-not to use it (e.g. that it isn't needed if you already know the type or have a post ID).

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

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

With no annotations, the description carries the full burden; it does usefully disclose the returned fields (title, score, comment count, subreddit, author, permalink), which matters since there is no output schema. However, it says nothing about authentication requirements, rate limits, or how pagination behaves despite an `after` cursor being supported.

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 with the primary action front-loaded, then the return shape, then sort options. No filler or redundancy.

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 six-parameter read tool with no annotations and no output schema, the description covers purpose, scope, return fields, and sort modes adequately. The remaining gaps (time filter, pagination via `after`, auth/rate behavior) are minor since the schema documents the parameters.

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%, so the schema already documents all six parameters including enums for sort and time; the description only echoes the sort options and the subreddit scoping. It adds no format or behavioral detail beyond the schema, so baseline 3 applies.

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 ("Search Reddit posts") plus the scoping option ("optionally scoped to a subreddit"), which implicitly separates it from siblings like search_communities and search_users. An agent can tell what this returns 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?

Usage is only implied: it's clear this is for keyword post search, but there is no explicit guidance on when to prefer it over get_community_posts, get_post, or search_communities, and no stated exclusions or prerequisites.

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

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

No annotations are supplied, so the description must carry the behavioral load. It usefully discloses the return payload, which reads as a read-only lookup, but says nothing about rate limits, result ordering, or empty-result behavior. Pagination exists but is only explained in the schema, not here.

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, front-loaded with the core action and followed by the return shape and a use case. No filler, though the third sentence borders on redundant with the first.

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 simple three-parameter keyword search with a fully documented schema and no output schema, the description covers purpose, return fields, and use case. Missing only result ordering and empty-result handling, which are minor for this complexity.

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%, including the pagination cursor and the 1-100 limit bound, so the baseline of 3 applies. The description adds mild value by framing the query as a keyword search over subreddit metadata, though it does not clarify matching semantics (name vs. description).

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: "Find subreddits by keyword," and enumerates what comes back (name, title, description, subscriber count, URL). It is clearly distinct from search_users and get_community_details in substance, but never names those siblings explicitly, so differentiation is inferred rather than stated.

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?

"Useful for discovering niche communities related to a topic" implies a discovery use case but gives no explicit when-to-use or when-not guidance. It does not tell the agent to prefer get_community_details once a name is known, nor when to use the generic search sibling instead.

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

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

No annotations exist, so the description carries the full burden. It usefully discloses the shape of the result (username, display name, description, profile URL), which confirms it is a read operation, but it says nothing about match semantics (prefix vs fuzzy), result ordering, or pagination behavior despite the cursor parameter.

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?

Two sentences, front-loaded with the action and followed by the return shape. Nothing is redundant or padded relative to the schema.

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?

The listed return fields compensate for the absent output schema, and the parameters are fully documented structurally. However, for a search tool with pagination and an adjacent exact-lookup tool, the description leaves the agent guessing about match behavior and when to prefer this over get_user_profile.

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%, so the schema already documents all three parameters including the 1–100 limit and the cursor semantics. The description adds only that the query matches username or display name, which is a marginal increment over the schema; baseline 3 is arguably earned but the addition is thin, so a 2 reflects that this dimension is essentially fully carried by 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?

The description names a specific verb and resource ("Find Reddit users") and specifies the search keys (username or display name), which lets an agent distinguish it from get_user_profile's exact lookup. It stops short of explicitly naming the sibling it differs from, so it lands at 4 rather than 5.

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?

There is no when-to-use or when-not-to-use guidance. With siblings like get_user_profile and the generic search tool present, the agent must infer that this tool is for partial-name discovery rather than exact profile retrieval, and nothing in the description states or excludes that.

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